16 Oh! That it were possible for me to undress the souls of those who swear frequently, and to expose to view the wounds and the bruises which they receive daily from oaths! We should then need neither admonition nor counsel; for the sight of these wounds would avail more powerfully than all that could be said, to withdraw from their wickedness even those who are most addicted to this wicked practice. Nevertheless, if it be not possible to spread before the eyes the shameful state of their soul, it may be possible to expose it to the thoughts, and to display it in its rottenness and corruption.
For as it says, “As a servant that is continually beaten will not be clear of a bruise, so he that swears and names God continually will not be purified of his sin.” It is impossible, utterly impossible, that the mouth which is practised in swearing, should not frequently commit perjury. Therefore, I beseech you all, by laying aside this dreadful and wicked habit, to win another crown. And since it is every where sung of our city, that first of all the cities of the world, she bound on her brow the name of Christians, so let all have to say, that Antioch alone, of all the cities throughout the world, has expelled all oaths from her own borders.
Yea, rather, should this be done, she will not be herself crowned alone, but will also carry others along with her to the same pitch of zeal. And as the name of Christians having had its origin here, has as it were from a kind of fountain overflown all the world, even so this good work, having taken its root and starting-point from hence, will make all men that inhabit the earth your disciples; so that a double and treble reward may arise to you, at once on account of your own good works, and of the instruction afforded to others.
This will be to you the brightest of diadems! This will make your city a mother city, not on earth, but in the heavens! This will stand by us at That Day, and bring us the crown of righteousness; which God grant that we may all obtain, through the grace and lovingkindness of our Lord Jesus Christ, with Whom to the Father, together with the Holy Spirit, be glory, now and ever, and world without end. Amen.
Source: Homilies on the Statues (New Advent)