15 And now, it is time that you should be teachers and guides of others; that friends should undertake to instruct and lead on their neighbours; servants their fellow-servants; and youths those of their own age. What if any one had promised you a single piece of gold for every man who was reformed, would you not then have used every exertion, and been all day long sitting by them, persuading and exhorting. Yet now God promises you not one piece of gold, nor ten, or twenty, or a hundred, or a thousand; no, nor the whole earth, for your labours, but He gives you that which is greater than all the world, the kingdom of heaven; and not only this, but also another thing besides it.
And what kind of thing is that? “He who takes forth the precious from the vile,” says He, “shall be as my mouth.” What can be equal to this in point of honour or security? What kind of excuse or pardon can be left to those, who after so great a promise neglect their neighbour's safety? Now if you see a blind man falling into a pit, you stretch forth a hand, and think it a disgraceful thing to overlook one who is about to perish? But daily beholding all your brethren precipitated into the wicked custom of oaths, do you not dare even to utter a word?
You have spoken once, perhaps, and he has not heard. Speak therefore twice, and thrice, and as often as it may be, till you have persuaded him. Every day God is addressing us, and we do not hear; and yet He does not leave off speaking. Do thou, therefore, imitate this tender care towards your neighbour. For this reason it is that we are placed with one another; that we inhabit cities, and that we meet together in churches, in order that we may bear one another's burdens, that we may correct one another's sins.
And in the same manner as persons inhabiting the same shop, carry on a separate traffic, yet put all afterwards into the common fund, so also let us act. Whatever advantages each man is able to confer upon his neighbour, let him not grudge, nor shrink from doing it, but let there be some such kind of spiritual commerce, and reciprocity; in order that having deposited every thing in the common store, and obtained great riches, and procured a large treasure, we may be all together partakers of the kingdom of heaven; through the grace and loving-kindness of our Lord Jesus Christ, by Whom and with Whom, to the Father, with the Holy Ghost, be glory, both now and ever, and world without end. Amen.
Source: Homilies on the Statues (New Advent)