About this we have much to say that is hard to explain, since you have become dull in understanding. 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; for everyone who lives on milk, being still an infant, is unskilled in the word of righteousness. But solid food is for the mature, for those whose faculties have been trained by practice to distinguish good from evil.