Nicene and Post-Nicene Fathers, Ser. II, Vol. XI:
The Works of John Cassian.: Chapter X. The answer how true discretion may be gained.

Chapter X.

The answer how true discretion may be gained.

Then Moses: True discretion, said he, is only secured by true humility. And of this p. 312 humility the first proof is given by reserving everything (not only what you do but also what you think), for the scrutiny of the elders, so as not to trust at all in your own judgment but to acquiesce in their decisions in all points, and to acknowledge what ought to be considered good or bad by their traditions. 1181 And this habit will not only teach a young man to walk in the right path through the true way of discretion, but will also keep him unhurt by all the crafts and deceits of the enemy. For a man cannot possibly be deceived, who lives not by his own judgment but according to the example of the elders, nor will our crafty foe be able to abuse the ignorance of one who is not accustomed from false modesty to conceal all the thoughts which rise in his heart, but either checks them or suffers them to remain, in accordance with the ripened judgment of the elders. For a wrong thought is enfeebled at the moment that it is discovered: and even before the sentence of discretion has been given, the foul serpent is by the power of confession dragged out, so to speak, from his dark under-ground cavern, and in some sense shown up and sent away in disgrace. For evil thoughts will hold sway in us just so long as they are hidden in the heart: and that you may gather still more effectually the power of this judgment I will tell you what Abbot Serapion did, 1182 and what he used often to tell to the younger brethren for their edification.

Footnotes

Cf. what is said on this subject in the Institutes, Book IV. c. ix.

Probably the author of Conference V., where see the note on c. i.