'Bond servants' in the Bible

Do you not know that if you surrender yourselves as bondservants to obey any one, you become the bondservants of him whom you obey, whether the bondservants of Sin (with death as the result)

You were set free from the tyranny of Sin, and became the bondservants of Righteousness--

For when you were the bondservants of sin, you were under no sort of subjection to Righteousness.

But now that you have been set free from the tyranny of Sin, and have become the bondservants of God, you have your reward in being made holy, and you have the Life of the Ages as the final result.

For men of that stamp are not bondservants of Christ our Lord, but are slaves to their own appetites; and by their plausible words and their flattery they utterly deceive the minds of the simple.