Discernment is…

Discernment is — and is recognized to be — a solid understanding of the will of God in all times, in all places, in all things; and is found only among those who are pure of heart, and body and in speech.
— Saint John Climacus (c. 525-606)

When you intend…

When you intend to do something then see that your thought is perturbed, and if, after invoking God’s Name, it remains perturbed even buy a hair’s breadth, know from this that the action you mean to commit is from the evil one, and refrain from committing it.
–Saint Barsanuphius the Great (Sixth Century)

Do nothing but…

Let us behave like temples of God, so that it may be clear that God dwells in us. Let our doings not fall away from the Spirit, but let us, who have begun to be heavenly and spiritual, consider and do nothing but heavenly and spiritual things.
–Saint Cyprian of Carthage (c. 200-258)