Ephesians 6:5

Your masters according to the flesh. — This phrase (used also in Colossians 3:12) at once implies the necessary limitation of all human slavery. It can subjugate and even kill the body, but it cannot touch the spirit; and it belongs only to the visible life of this world, not to the world to come. The slave is a man in spiritual and immortal being, not a “living tool” or “chattel,” as even philosophy called him.

With fear and trembling. — The phrase is a favourite one with St. Paul. (See 1 Corinthians 2:3; 2 Corinthians 7:15; Philippians 2:12, in all which cases it is applied to the condition of man as man under the weight of solemn responsibility before God.) It recognises the “spirit of bondage unto fear” (Romans 8:15) necessarily belonging to all who are “under law,” i.e., under obedience to the will of another, as enforced upon them by compulsion; and this fear, moreover, is viewed as showing itself in “trembling” anxiety to obey. So St. Peter commands (1 Peter 2:18), “Servants, be subject to your masters with all fear, not only to the good and gentle, but also to the froward;” and it is to be noted that he describes the suffering herein implied as a fellowship with the sufferings of the Lord Jesus Christ (Ephesians 6:21).

Singleness of your heart, as unto Christ. — The phrase “singleness of heart,” is here used in its proper sense, from which all others (see Romans 12:8; 2 Corinthians 8:2; 2 Corinthians 9:11; 2 Corinthians 9:13) may be derived. It means having but one aim, and that the one which we profess to have, with no duplicity of reservation or hypocrisy. Such singleness of heart cannot be given perfectly to any merely human service, because no such service has a right to our whole heart; hence St. Paul adds, “as unto Christ,” bidding them look on their service as a part of the service to Him who can claim absolute devotion.