Ye have need that one teach you again which are the first principles of religion. Accordingly these are enumerated in Hebrews 6:1. And have need of milk — The first and plainest doctrines.
Related Commentaries of Hebrews 5:12
Hebrews 5:12
12 For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat.