There are several points, they are to be taken TOGETHER, they will mean several posts (since post length here is restricted). I share NOT with the goal of changing anyone's mind on this but to share the perspective of Lutherans on this. Let me make clear too that there are several issues here...
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From Post 8:
Matthew 18:6, "If anyone causes one of these little ones who believe in me to sin..."
Is Jesus then saying that it is only a problem to offend children who were baptized? Or all children? But something else is going on in Chapter 18:
Verses 18:3-5 use
paidion
3 And said, Verily I say unto you, Except ye be converted, and become as
little children, ye shall not enter into the kingdom of heaven.
4 Whosoever therefore shall humble himself as this
little child, the same is greatest in the kingdom of heaven.
5 And whoso shall receive one such
little child in my name receiveth me.
But Verse 18:6 & 10 uses
mikros
6 But whoso shall offend one of these little ones which believe in me, it were better for him that a millstone were hanged about his neck, and that he were drowned in the depth of the sea.
10 Take heed that ye despise not one of these
little ones; for I say unto you, That in heaven their angels do always behold the face of my Father which is in heaven.
paidíon, pahee-dee'-on; neuter diminutive of
G3816; a childling (of either sex), i.e. (properly), an infant, or (by extension) a half-grown boy or girl; figuratively, an immature Christian:—(little, young) child, damsel.
mikrós, mik-ros'; apparently a primary word; small (in size, quantity, number or (figuratively) dignity):—least, less, little, small.
Is mikros rrefering to those who humble themselves as the little child. If so then verses 6 and 10 might be referring to adults with faith who have humbled themselves like a child. Paidion is not connected with "who believe in me," but micros is. So I am not sure these verses say anything about children's saving faith, just that children very easily believe what they are told (another reason not to send them to Caesar's schools). Hence, we should have a similar unquestioning faith in Jesus.
Mark 10:13-15, "People were bringing little children to Jesus to have Him touch them, but he disciples rebuked them. When Jesus saw this, he was indignant. He said to them, "Let the little children come to me and do not hinder them, for the kingdom of God belongs to such as these. I tell you the truth, anyone who will not receive the kingdom of God like a little child will never enter it."
This does seem to say that children are members of the Kingdom of God, but says nothing of baptism. Seems like a very general statement. Note various instances in the Old Testament where men under the age of 20 were not held accountable. I am not saying that everyone under 20 is automatically saved, but I am saying that it seems God has made special provision for the youth until they reach a point of maturity were they can count the cost of following Jesus (Luke 14:25-33).
Acts 2:38-39, "Repent and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of your sins. And you will receive the Holy Spirit. This promise is for you and your children and for all who are far off for all whom the Lord our God will call."
I believe the second part of this verse is simply saying that succeeding generations can also rely on this promise, not that babies should be baptized. And it does say "Repent and be baptized," not just, "be baptized."