Ephesians 6:8-9

8knowing that whatever good thing each one does, he will receive this back from the Lord, whether [he is] slave or free.

9You masters, do the same [showing goodwill] toward them, and give up threatening and abusive words, knowing that [He who is] both their true Master and yours is in heaven, and that there is no partiality with Him [regardless of one’s earthly status].