For when you were slaves of sin, you were free in regard to righteousness. What fruit did you have then in the things of which you are now ashamed? For the end of those things is death. But now having been set free from sin, and having become slaves of God, you have your fruit to holiness, and the end, everlasting life.
St. Paul speaks about us being slaves to sin – we act at times as though we cannot do otherwise but obey our sinful nature. However, he sees us being able to choose a different way – we can choose to make ourselves obedient to God, and thus servants/slaves of God. Sin and righteousness are not the only things to which we can become enslaved. Certainly people can become slaves to themselves – so totally trapped in self-centeredness and the demands of their own mind and bodies that they behave as slaves to their own desires.
“Do you not know that if you yield yourselves to any one as obedient slaves, you are slaves of the one whom you obey, either of sin, which leads to death, or of obedience, which leads to righteousness?” (Romans 6:16)
In the desert fathers we find this story about enslavement – we can become enslaved to anything that we value more than God or more than neighbor. It is love ultimately which frees us from all such enslavement:
There are times when a person will ignore large sums of money; nevertheless when it comes to a small needle, one’s attachment to it may cause one much trouble. Then, the small needle replaces the large amount of money. Therefore, one becomes a slave of the needle, or the monastic cap, or the handkerchief, or the book, instead of being a servant of God. (Amma Dionysia, In the Heart of the Desert, pg. 130)