Augustine of Hippo — as excerpted in the Catena Aurea on Matthew 5:38-42

“(ubi sup.) The other kind of injuries are those in which full restitution can be made, of which there are two kinds; one relates to money, the other to work; of the first of these it is He speaks when He continues, Whoso will sue thee for thy coat, let him have thy cloak likewise. As by the cheek are denoted such injuries of the wicked as admit of no restitution but revenge, so by this similitude of the garments is denoted such injury as admits restitution. And this, as the former, is rightly taken of preparation of the heart, not of the show of the outward action. And what is commanded respecting our garments, is to be observed in all things that by any right we call our own in worldly property. For if the command be expressed in these necessary articles of life, how much more does it hold in the case of superfluities and luxuries? And when He says, He who will sue thee, He clearly intends to include every thing for which it is possible that we should be sued. It may be made a question whether it is to be understood of slaves, for a Christian ought not to possess his slave on the same footing as his horse; though it might be that the horse was worth the more money. And if your slave have a milder master in you than he would have in him who seeks to take him from you, I do not know that he ought to be given up as lightly as your coat.”