Adam Clarke on Ephesians 6:9

Ye masters, do the same things unto them - Act in the same affectionate, conscientious manner towards your slaves and servants, as they do towards you.

Forbearing threatening - If they should transgress at any time, lean more to the side of mercy than justice; and when ye are obliged to punish, let it be as light and as moderate as possible; and let revenge have no part in the chastisement, for that is of the devil, and not of God.

The words, forbearing threatening; ανιεντες την απειλην, signify to mitigate, relax, or not exact threatening; that is, the threatened punishment. The sense is given above.

In Shemoth Rabba, sect. 21, fol. 120, there is a good saying concerning respect of persons: "If a poor man comes to a rich man to converse with him, he will not regard him; but if a rich man comes he will hear and rehear him. The holy and blessed God acts not thus; for all are alike before him, women, slaves, the poor, and the rich."

Knowing that your Master also is in heaven - You are their masters, God is yours. As you deal with them, so God will deal with you; for do not suppose, because their condition on earth is inferior to yours, that God considers them to be less worthy of his regard than you are; this is not so, for there is no respect of persons with Him.