Thanks Godsgood for your mention of this verse. 'Little children' is a phrase used to describe all true believers. Even in the verse you quoted, we can see that. That is because the verse says that when one is converted they become as 'little children'. Even if they are older than children physically. The name 'Paul', for example, means 'little'. And yet Paul was an adult when he was converted. Other scriptures showing that the term is referring to all true believers are:
"Little children, keep yourselves from idols. Amen "
"Ye are of God, little children, and have overcome them: because greater is he that is in you, than he that is in the world. "
"My little children, let us not love in word, neither in tongue; but in deed and in truth. "
"Little children, let no man deceive you: he that doeth righteousness is righteous, even as he is righteous. "
"And now, little children, abide in him; that, when he shall appear, we may have confidence, and not be ashamed before him at his coming. "
"Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time."
" I write unto you, little children, because ye have known the Father. "
"I write unto you, little children, because your sins are forgiven you for his name's sake. "
"But Jesus said, Suffer little children, and forbid them not, to come unto me: for of such is the kingdom of heaven. "
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When Saul of Tarsus studied in a bible school was never a Little Children of God because he Trusted Man (Jeremiah 17:5) to have the knowledge about the word of God.
ACTS 22:3
3 I am verily a man which am a Jew, born in Tarsus, a city in Cilicia, yet brought up in this city at the feet of Gamaliel, and taught according to the perfect manner of the law of the fathers, and was zealous toward God, as ye all are this day.
All he learned from Gamaliel he considered it as losses.
PHILIPPIANS 3:8
8 Yea doubtless, and I count all things but loss for the excellency of the knowledge of Christ Jesus my Lord: for whom I have suffered the loss of all things, and do count them but dung, that I may win Christ,
When he became Little Children of God and his name became Paul, he never trusted Man again but God to teach him.
JAMES 1:5-8
5 If any of you lack wisdom, let him ask of God, that giveth to all men liberally, and upbraideth not; and it shall be given him.
6 But let him ask in faith, nothing wavering. For he that wavereth is like a wave of the sea driven with the wind and tossed.
7 For let not that man think that he shall receive any thing of the Lord.
8 A double minded man is unstable in all his ways.
Although Paul and Jesus Christ never met face to face (Unlike 11 Apostles) but Jesus Christ in on his way he taught Paul about the words of God.
GALATIANS 1:11-12
11 But I certify you, brethren, that the gospel which was preached of me is not after man.
12 For I neither received it of man, neither was I taught it, but
by the revelation of Jesus Christ.
This is why almost books in New Testament have written by Paul. All these is from Jesus Christ.
The situation of Paul by that time is same as our situation today in which Jesus Christ is no longer in this world.
But if we want to become God's Little Children we must trust God to teach us about God's words and never ask any man.