9 I wrote to the assembly, but Diotrephes, who loves to be first among them, doesn’t accept what we say. 10 Therefore, if I come, I will call attention to his deeds which he does, unjustly accusing us with wicked words. Not content with this, neither does he himself receive the brothers, and those who would, he forbids and throws out of the assembly.
11 Beloved, don’t imitate that which is evil, but that which is good. He who does good is of God. He who does evil hasn’t seen God.
12 Demetrius has the testimony of all, and of the truth itself; yes, we also testify, and you know that our testimony is true.
Matthew Henry's Commentary on 3 John 1:9-12
Commentary on 3 John 1:9-12
(Read 3 John 1:9-12)
Both the heart and mouth must be watched. The temper and spirit of Diotrephes was full of pride and ambition. It is bad not to do good ourselves; but it is worse to hinder those who would do good. Those cautions and counsels are most likely to be accepted, which are seasoned with love. Follow that which is good, for he that doeth good, as delighting therein, is born of God. Evil-workers vainly pretend or boast acquaintance with God. Let us not follow that which is proud, selfish, and of bad design, though the example may be given by persons of rank and power; but let us be followers of God, and walk in love, after the example of our Lord.