Father Mark talks about maturity and immaturity in both adults and children, with 1 Corinthians 13:11-12, as a starting point.

“When I was a child, I used to talk as a child, think as a child, reason as a child; when I became a man, I put aside childish things. At present we see indistinctly, as in a mirror, but then face to face. At present I know partially; then I shall know fully, as I am fully known.”