This is a tremendously sensitive topic to discuss. I know that many who ask this question do so not from a place of purely academic interest. This is a personal and often painful question. But the emotion behind it should not be used to suggest that this is anything less than an honest question by many godly people. There is a real genuine desire to know what happens to infants. While the Bible does not answer this question explicitly, it does, I believe, give us enough information to draw the conclusion that infants who die go to heaven.
We should begin by setting up the dilemma. Christianity teaches that all men are born sinful (Rom. 3:23), they cannot save themselves and are separated from God as a result of their sin. The Bible also teaches that salvation is contingent upon faith expressed in the finished work of Christ (Eph. 2:8). An infant, however, cannot express faith in the finished work of Christ, nor confess their sinfulness. So, we see here the dilemma before us: how can children be said to go to heaven when they are unable to repent of their sins and put their faith in Christ.
There have been a number of attempts to answer this question. Some turn to baptism as a means of procuring salvation for infants. I will not go into a full defense of confessor’s baptism here, but we can say at least this: (1) there are no cases of infant baptism in the Bible. Not a single one. (2) To make baptism the means of salvation is to essentially make baptism more significant than Christ. For in such an arrangement salvation is contingent upon water baptism, not upon Jesus. As our senior pastor Bob Johnson has written elsewhere, “To say that only the babies who are baptized go to heaven, and that the babies who are not go to hell (as some teach), is to make the grounding of the infant’s salvation upon the efforts of someone other than Christ” (What Happens to Infants Who Die?, 1). Such a view diminishes the Biblical emphasis on the work of Christ as salvific.
An alternative view has been to argue for the innocence of children. The Bible does speak in some places of the “innocence” of children (Jer. 19:4; Ps. 106:38). We should be careful to assume that these verses mean more than they say. It is worthwhile to consider the Old Testament’s meaning behind such words. The Bible speaks of “innocent blood” in a number of places; many of those passages refer to adults who are “innocent” with regard to particular acts (2 Ki.21:16; Jer. 22:3; Ex 23:7). So, for example, Jeremiah 26 recounts the reaction of the officials of Judah to the prophet’s preaching. He forewarns the city of coming destruction if they do not repent. They, in response, decide to kill the messenger because they hate the message. But the prophet warns them that he is innocent of any wrong in this case and if they kill him they will “bring innocent blood” upon themselves and the whole city (v. 14). Now, is Jeremiah innocent of any moral failing? No, and that’s not the point of his rebuke. Original sin is not based upon our actions, but is inherent to our nature. Sin resides in our hearts, not simply in our hands. So Jeremiah was a sinner, yet in this instance he was not guilty of any sin that warranted his being put to death. That’s his point. In relation to the passages that speak of the “innocence” of children, then, we should not see them as contradicting passages like Romans 3:10-11 and 3:23. Rather we should understand these verses as arguing that the children are “innocent” of particular actions warranting their death. It is, we might say, a “conditional innocence,” not a complete moral purity.
The Bible teaches that sin resides in our hearts and as such we are all condemned before God (Eph. 2:3). Children are as sinful as their parents because they are born in sin, apart from God, and in desperate need of his rescue. So, there must be another solution to this dilemma.
The answer, I believe is found in the doctrine of election. The doctrine of election might seem a strange place to go for comfort on this issue, but this doctrine teaches that God saves all whom He predetermined to save. I won’t here give a full-fledged defense of the doctrine, but readers may look at a number of Scriptural references to help understand it (Romans 9; Ephesians 1:3-4; John 1:12-13; 15:16; 2 Thess. 2:13). The doctrine is a comfort in this case because it can provide a link between the child’s inability to believe and their salvation.
According to the doctrine of election not only is salvation an act of God’s grace, but even the imparting of faith is an act of God’s grace. So, Ephesians 2:8 tells us:
For by grace you have been saved through faith. And this is not your own doing; it is the gift of God
Most of us read this and assume that it teaches the “gift of God” refers exclusively to salvation in the context. The Greek, however, makes it evident that the whole content of the first sentence is a gift of God, meaning salvation through faith is a gift of God. The phrase “not of your own doing” helps us see the connection. It makes no sense grammatically to say that grace is a gift of God not of your own doing, for that is the very definition of grace: unmerited favor. Understanding that the “not of your own doing” refers to the whole statement “by grace you have been saved through faith” avoids the redundancy. We see the same idea communicated to Nicodemus, when Jesus says to him “You must be born again.” Nicodemus responds with more than curiosity saying, “How can a man be born when he is old? Can he enter a second time into his mother’s womb and be born” (John 3:4). Jesus’ response reveals the gift of faith; he says:
Jesus answered, “Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. 6 That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. 7 Do not marvel that I said to you, ‘You must be born again.’ 8 The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit.”
Jesus’ point is that being born again, i.e. spiritual regeneration which gives life to dead souls, is an act of the Spirit of God. He blows where he wishes.
In application to infants who die we see that they, like all men, may be granted faith via the Spirit of God apart from their own active expression of such faith. God loves little children, and because of their own inability to take responsibility for their sinfulness and faith God grants them faith as elect children that they may be saved. Again, it must be said that this cannot be directly found in Scripture, so, we must hold this conclusion somewhat loosely. But I believe we have solid ground to stand on here. The character of God, the doctrine of election, the compassion of our Savior all lead me to conclude without any real qualms that God saves infants who die. May all who know the pain of this reality find comfort in the love of God.
For further reading I highly recommend Bob Johnson’s little booklet: What Happens to Infants Who Die?
Pastor Dave Online 
Have you ever read Roy B. Zuck on this subject from his book, “Precious in His Sight: Childhood and Children in the Bible” This is also a helpful resource on this topic.