Do good (αγαθοποιητε). Third-class condition, εαν and present subjunctive. This verb not in old Greek, but in LXX.

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If you do good to them . . .—Actual deeds of kindness take the place in St. Luke which in St. Matthew is occupied by the …

St. John Chrysostom: The Lord had said that we must love our enemies. So that you would not think this was an exaggerated expr…

At this point we have a remarkable series of comparisons between the courtesies of believers and those of worldly people. Even “sinners” act decent…

And if you do good to them which do good to you
As one good turn deserves another:

These are hard lessons for flesh and blood. But if we are thoroughly grounded in the faith of Christ's love, this will make his commands easy for u…