Where in the Bible is it written “Be like children”?

The phrase "be like children" is not found in the Bible. However, there are several passages that speak to the importance of having a childlike faith.

One of the most well-known passages is Matthew 18:3-4, which says, "And he said: “Truly I tell you, unless you change and become like little children, you will never enter the kingdom of heaven. Therefore, whoever takes the lowly position of this child is the greatest in the kingdom of heaven." This passage speaks to the importance of having a humble, trusting faith like a child.

Another passage is Luke 18:16-17, which says, "But Jesus called the children to him and said, “Let the little children come to me, and do not hinder them, for the kingdom of God belongs to such as these. Truly I tell you, anyone who will not receive the kingdom of God like a little child will never enter it.” In this passage, Jesus is emphasizing the importance of having a childlike faith in order to receive the Kingdom of God.

A third passage is 1 Corinthians 13:11, which says, "When I was a child, I talked like a child, I thought like a child, I reasoned like a child. When I became a man, I put the ways of childhood behind me." In this passage, Paul is emphasizing the importance of growing up and maturing in our faith. He is not saying that we should remain in a childlike state, but rather that we should strive to grow and mature in our faith.

Overall, the Bible does not explicitly say "be like children," but it does emphasize the importance of having a childlike faith. This faith should be humble, trusting, and receptive, but it should also strive to grow and mature.