12 Knowing these things then, let us fortify ourselves with virtue on all sides, and thus we shall avert the wrath of God, and let us make the members of the body instruments of righteousness; and let us discipline eyes, and mouth, and hands, and feet, and heart, and tongue, and the whole body, to be employed only in the service of virtue. And let us remember those three precepts, of which I discoursed to your Charity, exhorting you to consider no one as an enemy, nor to speak evil of any one of those who have aggrieved you; and to expel from your mouth the evil custom of oaths.
And with respect to the two former precepts, we will discourse to you on another occasion; but we shall speak to you during the whole of the present week respecting oaths; thus beginning with the easier precept. For it is no labour at all to overcome the habit of swearing, if we would but apply a little endeavour, by reminding each other; by advising; by observing; and by requiring those who thus forget themselves, to render an account, and to pay the penalty. For what advantage shall we gain by abstinence from meats, if we do not also expel the evil habits of the soul?
Lo, we have spent the whole of this day fasting; and in the evening we shall spread a table, not such as we did on yester-eve, but one of an altered and more solemn kind. Can any one of us then say that he has changed his life too this day; that he has altered his ill custom, as well as his food? Truly, I suppose not! Of what advantage then is our fasting? Wherefore I exhort, and I will not cease to exhort, that undertaking each precept separately, you should spend two or three days in the attainment of it; and just as there are some who rival one another in fasting, and show a marvellous emulation in it; (some indeed who spend two whole days without food; and others who, rejecting from their tables not only the use of wine, and of oil, but of every dish, and taking only bread and water, persevere in this practice during the whole of Lent); so, indeed, let us also contend mutually with one another in abolishing the frequency of oaths.
For this is more useful than any fasting; this is more profitable than any austerity. And this same care which we display in abstaining from food, let us exhibit with respect to abstinence from oaths; since we shall be chargeable with the reproach of extreme folly, while we regard not things that are forbidden, and expend all our care upon things indifferent; for to eat is not forbidden, but to swear is forbidden; we, however, abstaining from those things that are permitted, daringly venture upon those things that are forbidden!
On this account I beseech your Charity to make some change, and to let the beginning of it be visible from this day. For if we spend the whole of the present fast with such zeal, having in this week attained the practice of not swearing at all; and in the following having extinguished wrath; and in that which succeeds it, having pulled up evil-speaking by the roots; and after that, having amended what yet remains; thus going forward in our course, we shall come little by little to the very summit of virtue; and we shall escape the present danger; and shall make God propitious; and the multitude will come back again to our city; and we shall teach the fugitives that we are to place our hopes of safety neither in security of place, nor in flight and retirement; but in piety of soul, and in virtue of manners.
And thus shall we obtain the good things of this and of the future life; which, God grant! We may all be found worthy of, by the grace and loving-kindness of our Lord Jesus Christ, through whom and with whom be glory to the Father, together with the Holy Ghost, now and for ever and ever. Amen.
Source: Homilies on the Statues (New Advent)