In applying the text treating the relationship between masters to slaves (Eph 6:5-9), most modern sermonizers will connect it with the employer-employee relationship. However, the landscape here is bigger than that and this text might be a word for any of us in relationships where there is a differential in power.
By the way, the previous relationships in the larger context dealt with such power relationships (e.g., husband and wife; parents/fathers and children). As in the previous instructions, Paul here addresses the less powerful member of the dyad first. This move alone recognizes that the weaker member of the couple is not all together powerless. There are some things they can think and do.
Also notice how much time Paul gives to the slaves (vv. 5-8) vs. the masters (just v. 9). Some conjecture that this is because there are more slaves than masters in the Christian movement; however, Paul spends more time talking about the husbands in the earlier text. (By the second century, the pagan Celsus will criticize Christianity for attracting primarily women, children and slave). More likely, Paul has weighed his comments to fit the needs of his readers at that time.
Again, this text can inform us whenever we are dealing with people in power or are ourselves the people in power. Thus, when working for others, whether for pay or as a volunteer, we should work as if we are working for Jesus. This is echoed in all three verses to the slaves: “as to Christ,” “as slaves to Christ,” and “as serving the Lord.” We can do this because the “Lord will reward everyone for what every good s/he does.”
Hidden from the English reader, the word “master” is actually the word “lord,” in the original—the same word used to speak of the Lord Jesus. Thus running through this text is the contrast between “earthly (fleshly) lords” (v. 5) and the Lord (v. 7). Masters, therefore, should treat their slaves well because the Lord is Lord of both.
Still, the most amazing comment is that the masters are to treat their slaves “in the same way” (v. 9) as the slaves treat the masters. How is that even possible?
In the ancient world, a husband could abuse his wife with impunity, fathers could beat their children without reprisals, and masters could treat slaves even worse—legally! In each case, here, Paul offers a surprising word to each.
Husbands are to love their wives even if they means dying for them, fathers are not to provoke their children, and masters are not to threaten their slaves. In each relationship, Paul introduces the radical revolution of submission.
And where did he learn this? Jesus. This is the way of Jesus.
As a husband and wife were to model the relationship between Christ and the church, Paul saw the day when all of our relationships—even the difficult ones—would also reflect the gospel of Christ’s love for the church, so to speak.