66 Hence, in this class of injuries which is atoned for by punishment, such a measure will be preserved by Christians, that, on an injury being received, the mind will not mount up into hatred, but will be ready, in compassion for the infirmity, to endure even more; nor will it neglect the correction, which it can employ either by advice, or by authority, or by [the exercise of] power. There is another class of injuries, where complete restitution is possible, of which there are two species: the one referring to money, the other to labour. And therefore examples are subjoined: of the former in the case of the coat and cloak, of the latter in the case of the compulsory service of one and two miles; for a garment may be given back, and he whom you have assisted by labour may also assist you, if it should be necessary. Unless, perhaps, the distinction should rather be drawn in this way: that the first case which is supposed, in reference to the cheek being struck, means all injuries that are inflicted by the wicked in such a way that restitution cannot be made except by punishment; and that the second case which is supposed, in reference to the garment, means all injuries where restitution can be made without punishment; and therefore, perhaps, it is added, “if any man will sue you at the law,” because what is taken away by means of a judicial sentence is not supposed to be taken away with such a degree of violence as that punishment is due; but that the third case is composed of both, so that restitution may be made both without punishment and with it. For the man who violently exacts labour to which he has no claim, without any judicial process, as he does who wickedly compels a man to go with him, and forces in an unlawful way assistance to be rendered to himself by one who is unwilling, is able both to pay the penalty of his wickedness and to repay the labour, if he who endured the wrong should ask it again. In all these classes of injuries, therefore, the Lord teaches that the disposition of a Christian ought to be most patient and compassionate, and thoroughly prepared to endure more.
67. But since it is a small matter merely to abstain from injuring, unless you also confer a benefit as far as you can, He therefore goes on to say, “Give to every one that asks you, and from him that would borrow of you turn not away.” “To every one that asks,” says He; not, Everything to him that asks: so that you are to give that which you can honestly and justly give. For what if he should ask money, wherewith he may endeavour to oppress an innocent man? What if, in short, he should ask something unchaste? But not to recount many examples, which are in fact innumerable, that certainly is to be given which may hurt neither yourself nor the other party, as far as can be known or supposed by man; and in the case of him to whom you have justly denied what he asks, justice itself is to be made known, so that you may not send him away empty. Thus you will give to every one that asks you, although you will not always give what he asks; and you will sometimes give something better, when you have set him right who was making unjust requests.
68. Then, as to what He says, “From him that would borrow of you turn not away,” it is to be referred to the mind; for God loves a cheerful giver. Moreover, every one who accepts anything borrows, even if he himself is not going to pay it; for inasmuch as God pays back more to the merciful, whosoever does a kindness lends at interest. Or if it does not seem good to understand the borrower in any other sense than of him who accepts of anything with the intention of repaying it, we must understand the Lord to have included those two methods of doing a favour. For we either give in a present what we give in the exercise of benevolence, or we lend to one who will repay us. And frequently men who, setting before them the divine reward, are prepared to give away in a present, become slow to give what is asked in loan, as if they were destined to get nothing in return from God, inasmuch as he who receives pays back the thing which is given him. Rightly, therefore, does the divine authority exhort us to this mode of bestowing a favour, saying, “And from him that would borrow of you turn not away:” i.e., do not alienate your goodwill from him who asks it, both because your money will be useless, and because God will not pay you back, inasmuch as the man has done so; but when you do that from a regard to God's precept, it cannot be unfruitful with Him who gives these commands.
Source: Our Lord's Sermon on the Mount (New Advent)