Hebrews 5:9-12

9And being made perfect, he became the author of eternal salvation to all them that obey him;

10Called by God an high priest after the order of Melchizedek. 11Of whom we have many things to say, and hard to be uttered, seeing ye are dull of hearing. 12For when for the time ye ought to be teachers, ye have need of one to teach you again which are the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat.