Romans 6:16
Do you not know that when you surrender yourselves as slaves to any one to obey him, you are his slaves whom you obey; whether it be sin, whose end is death, or obedience, whose end is righteousness?
John 8:34
"In solemn truth I tell you," Jesus replied, "every one who commits sin is a slave
2 Peter 2:19
They promise them liberty, while they themselves are slaves of rottenness! (For indeed a man is the slave of anything which masters him.)
Matthew 6:24
"No slave can serve two masters, for either he will hate the one and love the other, or he will pay heed to the one and despise the other. You cannot be the slaves both of God and of gold.
Romans 6:12-13
Therefore let not sin rule as king in your mortal body, compelling you to obey its lusts.
Romans 6:17
But God be thanked that you who were once the slaves of sin have obeyed from your hearts that type of teaching to which you were appointed;