And said, Verily I say unto you, Except ye be {b} converted, and become as little children, ye shall not enter into the kingdom of heaven.

(b) An idiom taken from the Hebrews which is equivalent to repent.

People's New Testament

18:3 Except ye be converted. The Revised Version translates, Except ye turn, which is correct. The Greek word strepho translated in the Common Version be converted is found in the New Testament in the active voice in every instance but one, and means to turn. It means something that the subject is to do, not something that is to be done for him.

Become as little children. Humble, teachable and free from selfish ambition, like little children.

Ye shall not enter into the kingdom of heaven. Instead of discussing who should be greatest in the kingdom of heaven, they had better inquire whether they were going to get in at all.

Wesley's Notes

18:3 Except ye be converted - The first step toward entering into the kingdom of grace, is to become as little children: lowly in heart, knowing yourselves utterly ignorant and helpless, and hanging wholly on your Father who is in heaven, for a supply of all your wants. We may farther assert, (though it is doubtful whether this text implies so much,) except ye be turned from darkness to light, and from the power of Satan to God:, except ye be entirely, inwardly changed, renewed in the image of God, ye cannot enter into the kingdom of glory. Thus must every man be converted in this life, or he can never enter into life eternal. Ye shall in no wise enter - So far from being great in it. Matt 19:14.

Matthew Henry's Concise Commentary

18:1-6 Christ spoke many words of his sufferings, but only one of his glory; yet the disciples fasten upon that, and overlook the others. Many love to hear and speak of privileges and glory, who are willing to pass by the thoughts of work and trouble. Our Lord set a little child before them, solemnly assuring them, that unless they were converted and made like little children, they could not enter his kingdom. Children, when very young, do not desire authority, do not regard outward distinctions, are free from malice, are teachable, and willingly dependent on their parents. It is true that they soon begin to show other dispositions, and other ideas are taught them at an early age; but these are marks of childhood, and render them proper emblems of the lowly minds of true Christians. Surely we need to be daily renewed in the spirit of our minds, that we may become simple and humble, as little children, and willing to be the least of all. Let us daily study this subject, and examine our own spirits.