Since better writers/thinkers than me have already weighed in, I thought it might be useful to bring up a real-world historical example dealing with the problem of just when we might affirm someone's faith. This is a longish section out of Jonathan Edwards' excellent little work known as A Faithful Narrative where he tells the story of a small revival that broke out in his town. In this section, he relates the conversion of a four-year-old girl.
"But I now proceed to the other instance that I would give an account of, which is of the little child forementioned.6 Her name is Phebe Bartlet, daughter of William Bartlet. I shall give the account as I took it from the mouths of her parents, whose veracity none that know them doubt of.
She was born in March, in the year 1731. About the latter end of April, or beginning of May, 1735, she was greatly affected by the talk of her brother, who had been hopefully converted a little before, at about eleven years of age, and then seriously talked to her about the great things of religion. Her parents did not know of it at that time, and were not wont, in the counsels they gave to their children, particularly to direct themselves to her, by reason of her being so young, and as they supposed not capable of understanding: but after her brother had talked to her, they observed her very earnestly to listen to the advice they gave to the other children; and she was observed very constantly to retire several times in a day, as was concluded, for secret prayer; and grew more and more engaged in religion, and was more frequent in her closet; till at last she was wont to visit it five or six times in a day: and was so engaged in it, that nothing would at any time divert her from her stated closet exercises. Her mother often observed and watched her, when such things occurred, as she thought most likely to divert her, either by putting it out of her thoughts, or otherwise engaging her inclinations; but never could observe her to fail. She mentioned some very remarkable instances.
She once of her own accord spake of her unsuccessfulness, in that she could not find God, or to that purpose. But on Thursday, the last day of July, about the middle of the day, the child being in the closet where it used to retire, its mother heard it speaking aloud; which was unusual, and never had been observed before. And her voice seemed to be as of one exceeding importunate and engaged; but her mother could distinctly hear only these words (spoken in her childish manner, but seemed to be spoken with extraordinary earnestness, and out of distress of soul): "Pray, blessed Lord, give me salvation! I pray, beg, pardon all my sins!" When the child had done prayer, she came out of the closet, and came and sat down by her mother, and cried out aloud. Her mother very earnestly asked her several times what the matter was, before she would make any answer; but she continued exceedingly crying, and wreathing her body to and fro, like one in anguish of spirit. Her mother then asked her whether she was afraid that God would not give her salvation. She answered, "Yes, I am afraid I shall go to hell!" Her mother then endeavored to quiet her, and told her she would not have her cry; she must be a good girl, and pray every day, and she hoped God would give her salvation. But this did not quiet her at all; but she continued thus earnestly crying, and taking on for some time, till at length she suddenly ceased crying, and began to smile, and presently said, with a smiling countenance, "Mother, the kingdom of heaven is come to me!" Her mother was surprised at the sudden alteration, and at the speech; and knew not what to make of it, but at first said nothing to her. The child presently spake again, and said, "There is another come to me, and there is another; there is three." And being asked what she meant, she answered, "One is, 'Thy will be done'; and there is another, 'Enjoy him forever'"; by which it seems that when the child said, "There is three come to me," she meant three passages of its catechism that came to her mind.
After the child had said this, she retired again into her closet; and her mother went over to her brother's, who was next neighbor; and when she came back, the child, being come out of the closet, meets her mother with this cheerful speech, "I can find God now!" referring to what she had before complained of that she could not find God. Then the child spoke again, and said, "I love God!" Her mother asked her how well she loved God, whether she loved God better than her father and mother; she said, "Yes." Then she asked her whether she loved God better than her little sister Rachel. She answered, "Yes, better than anything!" Then her elder sister, referring to her saying she could find God now, asked her where she could find God. She answered, "In heaven." "Why," said she, "have you been in heaven?" "No," said the child. By this it seems not to have been any imagination of anything seen with bodily eyes, that she called God, when she said, "I can find God now." Her mother asked whether she was afraid of going to hell, and that made her cry. She answered, "Yes, I was; but now I shan't." Her mother asked her whether she thought that God had given her salvation. She answered, "Yes." Her mother asked her, when. She answered, "Today." She appeared all that afternoon exceeding cheerful and joyful. One of the neighbors asked her how she felt herself. She answered, "I feel better than I did." The neighbor asked her what made her feel better. She answered, "God makes me." That evening as she lay abed, she called one of her little cousins to her that was present in the room, as having something to say to him; and when he came, she told him that heaven was better than earth. The next day being Friday, her mother asking her her catechism, asked her what God made her for. She answered, "To serve him," and added, "everybody should serve God, and get an interest in Christ."
The same day the elder children, when they came home from school, seemed much affected with the extraordinary change that seemed to be made in Phebe: and her sister Abigail standing by, her mother took occasion to counsel her, how to improve her time, to prepare for another world: on which Phebe burst out in tears and cried out, "Poor Nabby!" Her mother told her she would not have her cry, she hoped that God would give Nabby salvation; but that did not quiet her, but she continued earnestly crying for some time; and when she had in a measure ceased, her sister Eunice being by her, she burst out again and cried, "Poor Eunice!" and cried exceedingly; and when she had almost done, she went into another room, and there looked upon her sister Naomi: and burst out again, crying "Poor Amy!" Her mother was greatly affected at such a behavior in the child, and knew not what to say to her. One of the neighbors coming in a little after, asked her what she had cried for. She seemed at first backward to tell the reason: her mother told her she might tell that person, for he had given her an apple: upon which she said she cried because she was afraid they would go to hell.
At night a certain minister, that was occasionally in the town was at the house, and talked considerably with her of the things of religion; and after he was gone she sat leaning on the table, with tears running out of her eyes: and being asked what made her cry, she said it was thinking about God. The next day being Saturday, she seemed a great part of the day to be in a very affectionate frame, had four turns of crying, and seemed to endeavor to curb herself and hide her tears, and was very backward to talk of the occasion of it. On the Sabbath day she was asked whether she believed in God; she answered, "Yes." And being told that Christ was the Son of God, she made ready answer and said, "I know it."
From this time there has appeared a very remarkable abiding change in the child: she has been very strict upon the Sabbath; and seems to long for the Sabbath day before it comes, and will often in the week time be inquiring how long it is to the Sabbath day, and must have the days particularly counted over that are between, before she will be contented. And she seems to love God's house, is very eager to go thither. Her mother once asked her why she had such a mind to go, whether it was not to see fine folks. She said no, it was to hear Mr. Edwards preach. When she is in the place of worship, she is very far from spending her time there as children at her age usually do, but appears with an attention that is very extraordinary for such a child. She also appears very desirous at all opportunities to go to private religious meetings; and is very still and attentive at home in prayer time, and has appeared affected in time of family prayer. She seems to delight much in hearing religious conversation: when I once was there with some others that were strangers, and talked to her something of religion, she seemed more than ordinarily attentive; and when we were gone, she looked out very wistfully after us, and said, "I wish they would come again!" Her mother asked her why: says she, "I love to hear 'em talk!"
She seems to have very much of the fear of God before her eyes (Psalms 36:1), and an extraordinary dread of sin against him; of which her mother mentioned the following remarkable instance. Some time in August, the last year, she went with some bigger children to get some plums in a neighbor's lot, knowing nothing of any harm in what she did; but when she brought some of the plums into the house, her mother mildly reproved her and told her that she must not get plums without leave, because it was sin: God had commanded her not to steal. The child seemed greatly surprised, and burst out in tears, and cried out, "I won't have these plums!" and turning to her sister Eunice, very earnestly said to her, "Why did you ask me to go to that plum tree? I should not have gone if you had not asked me." The other children did not seem to be much affected or concerned; but there was no pacifying Phebe. Her mother told her she might go and ask leave, and then it would not be sin for her to eat them; and sent one of the children to that end; and when she returned, her mother told her that the owner had given leave, now she might eat them, and it would not be stealing. This stilled her a little while; but presently she broke out again into an exceeding fit of crying: her mother asked her what made her cry again; why she cried now, since they had asked leave. What it was that troubled her now? And asked her several times very earnestly, before she made any answer; but at last [she] said it was because—because it was sin! She continued a considerable time crying; and said she would not go again if Eunice asked her an hundred times; and she retained her aversion to that fruit for a considerable time, under the remembrance of her former sin.
She at some times appears greatly affected, and delighted with texts of Scripture that come to her mind. Particularly, about the beginning of November, the last year, that text came to her mind, Revelation 3:20, "Behold, I stand at the door and knock: if any man hear my voice and open the door, I will come in and sup with him, and he with me." She spoke of it to those of the family with a great appearance of joy, a smiling countenance, and elevation of voice, and afterwards she went into another room, where her mother overheard her talking very earnestly to the children about it, and particularly heard her say to them, three or four times over, with an air of exceeding joy and admiration, "Why, it is to sup with God." At some time about the middle of winter, very late in the night, when all were abed, her mother perceived that she was awake, and heard her as though she was weeping. She called to her, and asked her what was the matter. She answered with a low voice, so that her mother could not hear what she said; but thinking that it might be occasioned by some spiritual affection, said no more to her; but perceived her to lie awake, and to continue in the same frame, for a considerable time. The next morning, she asked her whether she did not cry the last night: the child answered, "Yes, I did cry a little, for I was thinking about God and Christ, and they loved me." Her mother asked her whether to think, of God and Christ's loving her made her cry: she answered, "Yes, it does sometimes."
She has often manifested a great concern for the good of others' souls: and has been wont many times affectionately to counsel the other children. Once about the latter end of September, the last year, when she and some others of the children were in a room by themselves, a husking Indian corn, the child after a while came out and sat by the fire. Her mother took notice that she appeared with a more than ordinary serious and pensive countenance, but at last she broke silence and said, "I have been talking to Nabby and Eunice." Her mother asked her what she had said to 'em. "Why," said she, "I told 'em they must pray, and prepare to die, that they had but a little while to live in this world, and they must be always ready." When Nabby came out, her mother asked her whether she had said that to them. "Yes," said she, "she said that, and a great deal more." At other times, the child took her opportunities to talk to the other children about the great concern of their souls, sometimes so as much to affect them and set them into tears. She was once exceeding importunate with her mother to go with her sister Naomi to pray: her mother endeavored to put her off; but she pulled her by the sleeve, and seemed as if she would by no means be denied. At last her mother told her that Amy must go and pray herself; "but," says the child, "she will not go"; and persisted earnestly to beg of her mother to go with her.
She has discovered an uncommon degree of a spirit of charity; particularly on the following occasion. A poor man that lives in the woods had lately lost a cow that the family much depended on, and being at the house, he was relating his misfortune, and telling of the straits and difficulties they were reduced to by it. She took much notice of it, and it wrought exceedingly on her compassions; and after she had attentively heard him a while, she went away to her father, who was in the shop, and entreated him to give that man a cow: and told him that the poor man had no cow! that the hunters or something else had killed his cow! and entreated him to give him one of theirs. Her father told her that they could not spare one. Then she entreated him to let him and his family come and live at his house: and had much more talk of the same nature, whereby she manifested bowels of compassion to the poor (1 John 3:17).
She has manifested great love to her minister: particularly when I returned from my long journey for my health, the last fall, when she heard of it, she appeared very joyful at the news, and told the children of it, with an elevated voice, as the most joyful tidings; repeating it over and over, "Mr. Edwards is come home! Mr. Edwards is come home!" She still continues very constant in secret prayer, so far as can be observed (for she seems to have no desire that others should observe her when she retires, but seems to be a child of a reserved temper), and every night before she goes to bed, will say her catechism, and will by no means miss of it: she never forgot it but once, and then after she was abed, thought of it and cried out in tears, "I han't said my catechism!" and would not be quieted till her mother asked her the catechism as she lay in bed. She sometimes appears to be in doubt about the condition of her soul, and when asked whether she thinks that she is prepared for death, speaks something doubtfully about it. At other times she seems to have no doubt, but when asked replies "Yes" without hesitation."
Now, what are we to make of this? And you'll note I'm dodging around the "baptism" issue, as Edwards was a Congregationalist and so such the girl would have already been baptized. But we still are faced with the question of what a church should do when faced with this kind of situation? Of course, on the one hand we might note that this is an exceptional circumstance--most four-year-old girls aren't giddy over the WSC, mournful over their sins, and desperately worried about the safety of the local preacher.
We should note that whatever decision is made about affirming or not affirming children, some flexibility for exceptional circumstances should be allowed. Children with terminal diseases (God forbid!), war time situations, places where persecution is rife, all of these need to be considered and accounted for by the church and given maximum flexibility in the rules and in our thoughts.
But even with our exceptions for exceptional circumstances, what about normal circumstances? In the regular course of events when your child barely out of toddler-hood says "I'm a Christian, can I take communion/be baptized/attend member's meetings?" we are going to have to answer both as parents (non-authoritatively) and as members of the church (authoritatively). Edwards in this case responded with a "yes, you can", though he admitted that such was not the normal course of events. I think the answer is... I don't know.
I mean, in one sense the answer as a parent is pretty easy. Well, "easy", at any rate. The correct response if my four-year-old (not that I have one of those right now) to "daddy am I a Christian?" is "we'll have to wait and see what you think when you're older and what the church says about your application for membership, my job is to teach you not to make final judgments on whether it takes or not." I say that's the easy answer because it's the right answer of course ;) but also because it kicks the responsibility off onto the church. Of course it's not really "easy" because telling someone you don't know if they're a Christian does carry certain implications with it, since there are implications for not being a Christian, and that can be hard when that someone is your own offspring.
It's as a church member where we are obligated to speak with some authority where it gets difficult. As those with the authority to admit someone into membership and so make a public declaration about the state of their faith, this is something we need to do carefully and seriously with each individual. We need to be sure that we are giving full consideration to each request, including judging the sincerity of the applicant and the possibility that a few years down the road they will be equally sincere. Here is probably where most people are going to struggle with toddler-faith. Sure, they claim to believe in Christ now, but ten years from now will they have to be excommunicated for apostasy or simply stripped from the rolls as never having been believers in the first place. (Though we could also say the same about someone who has a history of bouncing back and forth between belief and unbelief.) What do we do?
We ask Jonathan Leeman, that's what :)