4 Lately, I addressed to your Charity many things concerning the snares lying on all sides of us; and concerning fear and sadness, sorrow and pleasure; and also concerning the sickle that flies down upon the houses of swearers. Now, out of all these many matters, I would have you especially to remember what I said respecting the “winged sickle,” and its settling in the swearer's house; and pulling down the stones and the wood, and consuming the whole mass. And withal, take heed to this; that it is the extreme of folly to swear by taking the Gospels, and to turn the very Law which forbids swearing into an oath; and that it is better to suffer loss of property than to impose an oath on our neighbours; since this is a great honour to be done to God.
For when you say to God, “For your sake I have not put such a one, who has robbed and injured me, on his oath,” God will pay you back a great recompense on account of this honour, both here and hereafter. Say these things to others, and observe them also yourselves. I know that in this place we become more reverent, and lay aside every evil habit. But what is to be aimed at is, not that we be lovers of wisdom here only, but that when we depart, we may take this reverence out with us, where we especially need it.
For those who carry water do not merely have their vessels full when near the fountain, and empty them when they reach home, but there they put them away with special caution, that they may not be overturned, and their labours rendered useless. Let us all imitate these persons; and when we come home, let us strictly retain what has been spoken; since if you here have gotten full, but return home empty, having the vessels of your understandings destitute of what you have heard, there will be no advantage from your replenishment here. Show me not the wrestler in the place of exercise, but of actual contest; and religion not at the season of hearing, but at the season of practice.
Source: Homilies on the Statues (New Advent)