6:5-9 The duty of servants is summed up in one word, obedience. The servants of old were generally slaves. The apostles were to teach servants and masters their duties, in doing which evils would be lessened, till slavery should be rooted out by the influence of Christianity. Servants are to reverence those over them. They are to be sincere; not pretending obedience when they mean to disobey, but serving faithfully. And they must serve their masters not only when their master's eye is upon them; but must be strict in the discharge of their duty, when he is absent and out of the way. Steady regard to the Lord Jesus Christ will make men faithful and sincere in every station, not grudgingly or by constraint, but from a principle of love to the masters and their concerns. This makes service easy to them, pleasing to their masters, and acceptable to the Lord Christ. God will reward even the meanest drudgery done from a sense of duty, and with a view to glorify him. Here is the duty of masters. Act after the same manner. Be just to servants, as you expect they should be to you; show the like good-will and concern for them, and be careful herein to approve yourselves to God. Be not tyrannical and overbearing. You have a Master to obey, and you and they are but fellow-servants in respect to Christ Jesus. If masters and servants would consider their duties to God, and the account they must shortly give to him, they would be more mindful of their duty to each other, and thus families would be more orderly and happy.
5. Servants—literally, "slaves."
masters according to the flesh—in contrast to your true and heavenly Master (Eph 6:4). A consolatory him that the mastership to which they were subject, was but for a time [Chrysostom]; and that their real liberty was still their own (1Co 7:22).
fear and trembling—not slavish terror, but (See on 1Co 2:3; 2Co 7:15) an anxious eagerness to do your duty, and a fear of displeasing, as great as is produced in the ordinary slave by "threatenings" (Eph 6:9).
singleness—without double-mindedness, or "eye service" (Eph 6:6), which seeks to please outwardly, without the sincere desire to make the master's interest at all times the first consideration (1Ch 29:17; Mt 6:22, 23; Lu 11:34). "Simplicity."