Adam Clarke on 1 Timothy 6:1

Let as many servants as are under the yoke - The word δουλοι here means slaves converted to the Christian faith; and the ζυγον, or yoke, is the state of slavery; and by δεσποται, masters, despots, we are to understand the heathen masters of those Christianized slaves. Even these, in such circumstances, and under such domination, are commanded to treat their masters with all honor and respect, that the name of God, by which they were called, and the doctrine of God, Christianity, which they had professed, might not be blasphemed - might not be evilly spoken of in consequence of their improper conduct. Civil rights are never abolished by any communications from God's Spirit. The civil state in which a man was before his conversion is not altered by that conversion; nor does the grace of God absolve him from any claims, which either the state or his neighbor may have on him. All these outward things continue unaltered. See the notes on Eph 6:5, etc.; and 1Cor 7:21 (note), etc., and especially the observations at the end of that chapter.