10 We might continue to speak not only of these things, but also of many others, which are even more profound; and might moralise even upon the Creation itself; but reserving these subjects for the morrow, let us earnestly endeavour to retain what has been said, and to convey it to the rest. I know indeed, that the abstruseness of these speculations has seemed strange to your ears; but if we be a little vigilant, and accustom ourselves to them, we shall easily be able to teach others.
Meanwhile, it is necessary farther to say this to your Charity. Even as God has given us glory by means of this great creation, so let us also glorify Him by a pure conversation! “The heavens declare the glory of God,” though only seen; and we therefore should declare God's glory not only in speaking, but in silence, and in astonishing all men by the brightness of our life. For He says, “Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven.” For when an unbeliever beholds you, who art a believer, subdued, modest, and orderly in manners, he will wonder and say, “Truly great is the God of the Christians!
What manner of men has He formed? What, and from what has He made them? Hath He turned them from men into angels? If any one treats them contemptuously, they revile not! If any one beats them, they are not enraged! If any one does them an injury, they pray for him who has put them in pain! They have no enemy! They know nothing of cherishing malice! They are guiltless of vain babbling! They have not learned to utter a falsehood! They cannot endure a false oath, or rather, they swear not at all, but would prefer to have their tongue cut out, rather than to let an oath proceed out of their mouth!”
Such are the things which we should give them cause to say of us; and we should exterminate our evil habit of oaths, and pay at least as much honour to God, as we do to our more valuable garments. For how truly absurd is it, that when we have one garment better than the rest, we do not suffer ourselves to be continually wearing it; and yet everywhere we draggle about the name of God without concern, or ceremony! Let us not, I earnestly pray and beseech you, let us not thus despise our own salvation; but the care which we have used respecting this precept from the beginning, let us carry on even to the end.
For I thus continually exhort you on the subject of oaths, not as though condemning you of listlessness, but inasmuch as I have seen that you are for the most part reformed, I press you, and am urgent, that the whole work should be finished off, and come to its perfection. Even so act the spectators of public games. They excite those who are near the prize, with the more vehemence. Let us, then, by no means become weary; for we have nearly reached the completion of this amendment; and the difficulty was at the beginning.
But now that the greater part of the evil habit has been cut away, and less remains to correct, no labour is necessary, but we only need a moderate degree of watchfulness, and diligence for some short time, in order that we ourselves being amended, may also become instructors to others; and that we may behold the Holy Passover with much confidence, and that with much pleasure we may reap a double or treble measure of the customary gladness of the festival. For not so much does it delight us to be delivered from the toil and fatigue of fasting, as to meet that holy season with an illustrious and well-earned crown; a crown indeed that is never to fade!
Source: Homilies on the Statues (New Advent)