Romans 6:16
Know ye not that to whom ye present yourselves as slaves for obedience, his slaves ye are whom ye obey, whether of sin unto death, or obedience unto righteousness?
John 8:34
Jesus answered them, "Verily, verily, I say to you, every one who commits sin is a slave of sin.
2 Peter 2:19
promising them liberty, while they themselves are slaves of corruption; for by what one is overcome by this he has become enslaved.
Matthew 6:24
"No one can serve two masters; for either he will hate the one, and love the other; or he will hold to one, and despise the other. Ye cannot serve God and Mammon.
Romans 6:12-13
Let not sin, therefore, reign in your mortal body, that ye should obey its desires;
Romans 6:17
But thanks be to God that, though ye were slaves of sin, ye did, however, obey from the heart that form of teaching unto which ye were delivered;
Romans 6:19-23
I speak after human fashion because of the weakness of your flesh; for, as ye presented your members subservient to uncleanness, and to iniquity unto iniquity; so now present your members subservient to righteousness unto holiness.