Clement of Alexandria Stromata Book V But solid food belongs to those who are of full age, who by reason of use have their senses exercised so as to distinguish between good and evil. Wherefore, leaving the first principles of the doctrine of Christ, let us go on to perfection."[118] Clement of Alexandria Stromata Book VI Wherefore also, writing to the Hebrews, who were declining again from faith to the law, he says," Have ye not need again of one to teach you which are the first principles of the oracles of God, and are become such as have need of milk, and not of strong meat? "[114] Origen Against Celsus Book III But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil."[165] Origen Commentary on John Book I There is also an arche in a matter of learning, as when we say that the letters are the arche of grammar. The Apostle accordingly says:[81]