What does Paul require of Christian slaves in his detailed instructions to them? Eph. 6:5-8.

 Paul asks Christian slaves to obey their masters, offering heartfelt, excellent service. What is notable is his repeated reference to a grand substitution that he asks them to make. They are not to place their slave master in the place of Christ, offering to him the allegiance that belongs only to Christ. Rather, in the commitments and allegiance that motivate their heartfelt, excellent service they are to substitute Christ, the Lord, for the slave master. In encouraging this essential substitution, Paul is offering a transformed, Christian understanding of the master-slave relationship.

 Notice the several ways Paul presses this substitution upon them:

   Their slave masters are diminished by Paul as their “earthly masters,” pointing toward the real and heavenly Master (Eph. 6:5, ESV, emphasis supplied).
   They are to serve “with fear and trembling, with a sincere heart, as you would Christ” (Eph. 6:5, ESV, emphasis supplied).
   Paul notes this substitution most clearly in arguing that Christian slaves are to offer genuine service as slaves, not of their masters, but as “slaves of Christ” (Eph. 6:6, NIV).
   In performing their service, they are to do “the will of God from the heart,” offering heartfelt service directed to God (Eph. 6:6, NIV).
   Paul invites positively motivated service, offered “as to the Lord and not to man” (Eph. 6:7, ESV).
 For their heartfelt service, Christian slaves may expect full reward from Christ when He returns. They have done their work for Him and may expect reward from Him, an especially attractive idea for those trapped in this horrific institution. A slave might feel unappreciated or worse by an earthly master (compare 1 Pet. 2:19, 20). The believing slave, though, has a Master who is attentive, noticing “whatever good thing each one does” (Eph. 6:8, NASB), and offering sure reward.