However, another point is of interest. Many would deny that very young children, especially infants or toddlers, can have faith. However, I Samuel teaches otherwise. The story starts out with a barren Hannah who prays to the Lord and promises that she will dedicate her child to his service should the Lord provide her with one. After a mix-up over drunkenness (foreshadowing Pentecost) Eli, the high priest realizes she is praying and blesses her, and lo and behold she conceives. But here is where things get interesting for the paedofaith argument.
The next year Hannah declined to go with her husband and household to the annual sacrifice saying, , “As soon as the child is weaned, I will bring him, so that he may appear in the presence of the LORD and dwell there forever.”(1 Samuel 1:22 ESV). Now given different cultural practices weaning could be something that didn't occur until a child was four, five or even six years old. However, the text, by making such a point of it, gives the impression that Hannah only missed one of the anual sacrifices. Furthermore, it goes out of its way to tell us "the child was young" (v. 24b). This means that when she brought him up to be "lent to the LORD" he was probably less than two years old.
Yet the final sentence of chapter 1 verse 28 tells us "he worshipped the LORD." That is significant. This infant is credited with having "worshipped the LORD." Of course we shouldn't be surprised given what Jesus tells us, but it is something to ponder given our modern assumptions.
However, that is not all. Following this we have Hannah's magisterial song, glorifying God for his faithfulness and righteousness, and then immediately we find out that Elkanah (her husband, and by extension her and the family) went home "and the boy [Samuel] was ministering to the LORD in the presence of Eli the priest. I don't claim to know what this means precisely. But what it certainly does mean is that this small child (remember he had just been weaned) is described as having ministered to YAHWEH before the chief priest.
But to take things a step further, after finding out about the sins of Eli's sons (thus foreshadowing Samuel's adoptive place) we find out that Samuel was "ministering before the LORD clothed with a linen ephod," (the dress of a priest) and that "his mother used to make for him a little robe and take it to him each year..."
Taken together, what we have here is nothing less than a picture of infant faith growing an beginning to mature. The just weaned Samuel began, even then, to worship and minister to the Lord, and his faith and faithfulness grew throughout a lifetime.