Matthew 18:3

Be converted. Gr. strepho, “to turn,” or “to turn around”; hence, in reference to one’s course of conduct, “to change one’s mind.” In Biblical usage strepho is equivalent to the Heb. shub, commonly used throughout the OT of “turning” to the Lord (see Eze. 33:11; see on Jer. 3:12; Eze. 14:6; 18:30). Their ignorance of the nature of the kingdom of God’s divine grace was the occasion for the strife among the disciples that had led to the question, “Who is the greatest?” (see Matt. 18:1; DA 435). But there was another, and even more important cause — they were not truly “converted” (see DA 435). Unless they “turned” to follow Christ along the pathway upon which He had entered when He came to this world (see Phil. 2:6-8), their desires would become increasingly identified with those of the evil one (see John 8:44). Accordingly, Jesus now sought to inculcate in their minds an understanding of the principle of true greatness (see on Mark 9:35). Unless the disciples learned this principle they would never even enter the kingdom, to say nothing of enjoying a high position in it.

Become as little children. The spirit of rivalry cherished by the disciples had made them childish, but Jesus called upon them to become childlike. For Jesus’ personal attitude toward small children see on Mark 10:13-16.

Not enter. In the Greek there is a double negative, which emphasizes the utter impossibility. How imperfectly the disciples learned the lesson Christ sought to impart is apparent from two situations that developed some months later (see Matt. 20:20-28; Luke 22:24-30).