Hebrews 5:9-14

9 and having been made perfect, he became the source of eternal salvation for all who obey him,
10 having been designated by God a high priest according to the order of Melchizedek.
11 About this we have much to say that is hard to explain, since you have become dull in understanding.
12 For though by this time you ought to be teachers, you need someone to teach you again the basic elements of the oracles of God. You need milk, not solid food;
13 for everyone who lives on milk, being still an infant, is unskilled in the word of righteousness.
14 But solid food is for the mature, for those whose faculties have been trained by practice to distinguish good from evil.

Footnotes 1

New Revised Standard Version Bible, copyright 1989, Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.