'Masters' in the Bible

Slaves, be obedient to those who are your earthly masters, with respect for authority, and with a sincere heart [seeking to please them], as [service] to Christ—

You 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].