Ephesians 6:5-8
Slaves, be obedient to those who are your masters according to the flesh, with fear and trembling, in sincerity of heart, as to Christ;
Colossians 3:22-25
Slaves, in everything obey those who are your masters according to the flesh, not with eye-service, as men-pleasers, but in sincerity of heart, fearing the Lord.
Titus 2:9-10
Teach slaves to be subject to their masters in everything, to be well-pleasing, not to talk back to them,
1 Peter 2:18
Servants, be submissive to your masters with all respect, not only to those who are good and gentle, but also to those who are overbearing.