Romans 6:16
Do you not know that you are the slaves of whoever you offer your obedience to? If you obey [the desire to] sin, it leads to [spiritual] death; or if you obey [God] it leads to righteousness.
John 8:34
Jesus answered them, "Truly, truly, I tell you, everyone who commits sin is the slave of sin.
2 Peter 2:19
[Although] these people promise "liberty," they themselves are slaves to corrupting influences, for people are slaves to whatever controls them.
Matthew 6:24
No person can serve two masters, for he will either hate the one and love the other, or else he will cling to the one and look down on the other. You cannot serve God and material things [at the same time].
Romans 6:12-13
So, do not allow [the practice of] sin to rule your mortal bodies, so that you obey its desires.
Romans 6:17
Thank God that you people, who were once slaves to [the practice of] sin, became obedient from [your] heart to the pattern of teaching [i.e., the Gospel message] you committed yourself to.
Romans 6:19-23
I am using human reasoning because of your human weakness. For just as you once offered the parts of your bodies as slaves to impurity and to wickedness, which led to further wickedness; so now [you should] offer the parts of your body as slaves to do what is right, which leads to holy living.