Hebrews 5:12-14

Goodspeed(i) 12 For although from the length of your Christian experience you ought to be teaching others, you actually need someone to teach you over again the very elements of Christian truth, and you have come to need milk instead of solid food. 13 For anyone who is limited to milk is unacquainted with Christian teaching, for he is only an infant. 14 But full-grown men have a right to solid food, for their faculties are trained by practice to distinguish right and wrong.