But God be thanked, that you were the servants of sin, but you have obeyed from the heart that form of doctrine which was delivered you.
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Ambrosiaster
AD 400
As it is right to obey Christ, for he is himself righteousness and what he commands is righteous, Paul therefore says that we have become servants of righteousness “from the heart,” not from the law. We do this voluntarily and not out of fear, so that our confession of faith might find expression in the judgment of our mind. For by nature we have been led to faith, not by the law, in which standard of teaching we have been made for the rule of God, who created nature. For by nature we know by whom and through whom and in whom we were created. Therefore the standard of teaching is that into which our Creator has led us naturally. This is what he said above: “They are a law unto themselves,” when their own natures see what they believe, that what the law and the Prophets predicted to the Jews concerning Christ is what the Gentiles have confessed from the heart. For this reason Paul gives thanks to the Lord, because when we were still servants of sin we obeyed from the heart, believing in...
Thanks be to God He thanks God, not because they had been in sin, but because after having been so long under the slavery of sin, they had now been converted from their heart, and with their whole strength gave themselves to that form of doctrine to which they had been conducted by the gospel. He returns God thanks for their obedience to the faith, because this obedience of the human will is the work and gift of God, that so no one may glory in his sight. (Ephesians ii.) (Estius)
After shaming them by mentioning their slavery and alarming them by talking about its rewards, Paul puts the balance right by recalling the benefits which they have received. For by mentioning them he shows that they were set free from very great evils indeed and that this had happened without any labor on their part…. For no human power could have set us free from such great evils, but “thanks be to God,” who was willing and able to do such great things. And well he says that they were “obedient from the heart,” because they were neither forced nor pressed but came of their own accord, with a willing mind…. This shows that they exercised their free will.
