For when you were the servants of sin, you were free from righteousness.
Read Chapter 6
Ambrosiaster
AD 400
It is clear that whoever is free of God is a slave of sin. For as long as he sins he goes away from God and comes under sin. Commentary on Paul’s Epistles.
You were free from justice; that is, says St. Chrysostom, you lived as no ways subject to justice, nor obedient to the law and precepts of God: an unhappy freedom, a miserable liberty, worse than the greatest slavery, the end of which is death, eternal death: of which sins with great reason you are now ashamed, when you are become the servants of God, and obedient to him, for which you will receive the fruit and reward of everlasting life in heaven. (Witham)
In the past you did not split your service between righteousness and sin but were wholly given over to sin. So now that you have come over to the side of righteousness, you should do the same thing and give yourselves over entirely to righteousness, doing nothing at all that is wicked.
He who serves the devil is free from God, but he who being freed serves God is free from the devil. As a result it is apparent that a false liberty could have been had from a defect of the human will but that a true liberty could not have been received without the help of the liberator.