Personally, I believe all who die without faith in Jesus Christ will go to hell. This includes those who did not hear the Gospel because they were born in the wrong time or place, and those who did not live long enough to hear the Gospel and believe.
Whether I am wrong about this, or the preponderance of Christians are wrong, it should give us humility that apart from God’s grace giving us wisdom, we know absolutely nothing. Our hearts are hard like stone and the most obvious of things is utterly incomprehensible apart from God’s grace.
As God asks us to pray for wisdom so that He may grant it, let’s all pray for wisdom for this matter.
For God has shut up all in disobedience except babies so that He may show mercy to all. (Rom 11:32)
Among them we too all formerly lived in the lusts of our flesh, indulging the desires of the flesh and of the mind, and were by nature children of wrath, even as the rest, except babies. (Eph 2:3)
the intent of man’s heart, except babies, is evil from his youth (Gen 8:21)
There is none righteous, not even one, except babies; There is none who understands, except babies,There is none who seeks for God, except babies; All have turned aside, except babies, together they have become useless, except the babies; (Rom 3:10-12)
Now we know that whatever the Law says, it speaks to those who are under the Law, so that every mouth, except babies, may be closed and all the world, except babies, may become accountable to God (Rom 3:19)
for all, except babies, have sinned and fall short of the glory of God (Rom 3:23)
Therefore, just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all, except babies, sinned (Rom 5:12)
So then as through one transgression there resulted condemnation to all men, except babies, even so through one act of righteousness there resulted justification of life to all men. (Rom 5:18)
for “Whoever will call on the name of the Lord, except babies, will be saved.” How then will they call on Him in whom they have not believed? How will they believe in Him whom they have not heard? And how will they hear without a preacher? (Rom 10:13-14)
Two things stick out to me. First, unless we go out of our way to add “except babies” to each of those statements, it seems to me the statements sufficiently address all ages in the same way. Second, for those that say that supposedly elect babies have faith put in their hearts by God that no one can see, wouldn’t that contradict that faith comes from hearing a preacher, as it says in Romans 10:14? Obviously, infants cannot believe by being preached to.
I think Calvinists have a problem here. They have no problem with the doctrine of predestination, which essentially says that God deliberately saves some and not others. They base this doctrine upon the clear word of Scripture and rightly so. They also uphold the doctrines of original sin and total depravity, and rightly so, it puts all under condemnation so that God may have grace on all. Also, the more informed Calvinists will note that there will be fewer people in heaven than in hell, because the Scripture clearly says this as well.
So, if we can accept all these things, why are babies the stumbling point? Romans 9 specifically discusses how God created men (like Esau, whom He “hated”) that He would not save and in fact destine for destruction, so that His grace would be magnified. Why not make a single argument from silence, instead of several, and just presume that babies would be like anyone else who did not accept the Gospel and are apparently not predestined to be saved?
In order to ignore this simple logic, preachers like John MacArthur make brash assumptions: “Because God is by nature a savior and desires that all men come to repentance, and since God would have all men to be saved (!), there’s every reason to believe just from that alone, that a caring God that created that life to begin with, who superintends and guards that life, who knows intimately everything about that life, should that life perish physically in its infancy there would be every reason from that Psalm  alone to trust the nature of God that is by nature a savior on behalf of that life.”
What MacArthur said amounts to two things: infant universalism and a radically misinterpreted view of Psalm 139. I speculate, if MacArthur’s reason is sound, why wouldn’t God save all men after they die, regardless of age? Why does Romans 10:14 become untrue for the sake of his speculations?
Now, let’s look at Psalm 139:2-4, 13-17
You know when I sit down and when I rise up;
You understand my thought from afar.
You scrutinize my path and my lying down,
And are intimately acquainted with all my ways.
Even before there is a word on my tongue,
Behold, O Lord, You know it all. (…)
For You formed my inward parts;
You wove me in my mother’s womb.
I will give thanks to You, for I am fearfully and wonderfully made;
Wonderful are Your works,
And my soul knows it very well.
My frame was not hidden from You,
When I was made in secret,
And skillfully wrought in the depths of the earth;
Your eyes have seen my unformed substance;
And in Your book were all written
The days that were ordained for me,
When as yet there was not one of them.
How precious also are Your thoughts to me, O God!
How vast is the sum of them!
The message of the Psalm is simple. God knows everything we are going to say and do, for our whole lives, before we do them. David invokes his time in the womb to say that even then, God knew his future. To take this Psalm and say that this means infants are assured salvation takes several logical leaps and the ignoring of all the Scriptures I quoted above.
R.C. Sproul Jr. takes a more tempered view: “I don’t know [if babies are saved]. The Bible doesn’t say. It is certainly possible that they do. It is also possible that they don’t…Our emotions, however, should not lead us to add to the Bible, nor to muddy the precious saving waters of the work of Christ given to us by faith.”
My view? The Scripture teaches that God has shut up all in disobedience, including babies. Being that the Bible describes no means for non-believers to be saved, the presumption should always be that they are not. Anything else muddies the precious saving waters of the Work of Christ given to us by faith.