O Lord my God - A solemn appeal to God as to the sincerity and truth of what he was about to say.
If I have done this - This thing charged upon me, for it is evident that “Cush,” whoever he was, had accused him of some wrong thing - some wicked action. What that was can only be learned from what follows, and even this is not very specific. So far as appears, however, it would seem to be that he accused David of bringing evil, in some way, upon one who was at peace with him; that is, of wantonly and without provocation doing him wrong, and of so doing wrong that he had the avails of it in his own possession - some spoil, or plunder, or property, that he had taken from him. The charge would seem to be, that he had made a wanton and unprovoked attack on one who had not injured him, and that he had taken, and had still in his possession, something of value that properly belonged to another. Whether the accuser (Cush) in this referred to himself or to some other person, does not appear clear from the psalm; but as he was filled with rage, and as the life of David was endangered by him, it would seem most probable that the reference was to himself, and that he felt he had been personally wronged. The design of David, in the passage now before us, is to deny this charge altogether. This he does in the most explicit manner, by saying that this was so far from being true, that he had, on the contrary, delivered the life of him that was his enemy, and by adding that, if this were so, he would be willing that the injured man should persecute and oppose him, and even trample his life down to the earth.
If there be iniquity in my hands - That is, if there is the iniquity referred to; or, in other words, if he had in his possession what had been wrongfully taken from another, to wit, as appears, from this “Cush” who now accused him. The word “iniquity” here denotes an “unjust possession” - a property that had been unjustly taken from another; and, as remarked above, the slanderous charge would seem to have been, that he had taken that property from some one who was at peace with him, and that he retained it contrary to justice. This charge David means peremptorily to deny.