Hebrews 5:12-14 World English Bible (WEB)
12 For although by this time you should be teachers, you again need to have someone teach you the rudiments of the first principles of the revelations of God. You have come to need milk, and not solid food. 13 For everyone who lives on milk is not experienced in the word of righteousness, for he is a baby. 14 But solid food is for those who are full grown, who by reason of use have their senses exercised to discern good and evil.