Comp. Lu 6:28.

Bless, and curse not. Bless only; or continue to bless, however long or aggravated may be the injury. Do not be provoked to anger, or to cursing, by any injury, persecution, or reviling. This is one of the most severe and difficult duties of the Christian religion; and it is a duty which nothing else but religion will enable men to perform. To curse denotes, properly, to devote to destruction. Where there is power to do it, it implies the destruction of the object. Thus the fig-tree that was cursed by the Saviour soon withered away, Mr 11:21. Thus those whom God curses will be certainly destroyed, Mt 25:41. Where there is not power to do it, to curse implies the invoking of the aid of God to devote to destruction. Hence it means, to imprecate; to implore a curse from God to rest on others; to pray that God would destroy them. In a larger sense still, it means to abuse by reproachful words; to calumniate; or to express one's self in a violent, profane, and outrageous manner. In this passage it seems to have especial reference to this.

{h} "Bless them which persecute you" Mt 5:44