Thematic Bible: Those that are full of age

Concerning Him we have much to say, and much that it would be difficult to make clear to you, since you have become so dull of apprehension. For although, considering the long time you have been believers, you ought now to be teachers of others, you really need some one to teach you over again the very rudiments of the truths of God, and you have come to require milk instead of solid food. By people who live on milk I mean those who are imperfectly acquainted with the teaching concerning righteousness. read more.
Such persons are mere babes. But solid food is for adults--that is, for those who through constant practice have their spiritual faculties carefully trained to distinguish good from evil.