In what ways should we be like children and in what ways like adults?

One of the things that Jesus urged was simplicity, recommending that people become like little children (Matt. 18:3). Elsewhere Paul talked about putting childish ways behind him and growing up (1 Cor. 13). Why is that?

Is this one of those glaring contradictions that would-be de bunkers of the Bible like to point out?

How do you resolve this?

In what ways should we be like children and in what ways like adults?

With an Introductory paragraph (including underlined thesis ), at least 3 supporting paragraphs each containing a different supporting idea, and a conclusion. Cite using the two sources provided.