By this he wishes to put a strong bridle on his hearers. Once every way has been shut against each of them by the accusations of the Prophets, none can break loose or escape when the doctrine of faith is fully revealed.
The Prophets set forth three very grave charges: first, that all without exception did evil. Second, that they did evil without any admixture of good, giving themselves solely to vices. Finally, that they did evil with all their strength” (Chrysostom).
“As it is written” corresponds more directly to the translation: “we have already charged,” that is, we have already accused. Saint Paul takes the prior accusations from the Psalms and from the Prophet Isaiah.
First he cites prophecies that expose unrighteousness in general. Then he cites those that expose the chief forms of unrighteousness: impiety before God, lack of love, and evildoing toward neighbors.
It is noteworthy that impiety before God is placed both at the beginning and at the end. It should be understood as the source and fruit of unrighteousness toward neighbors.
The words “There is none righteous, no, not one” are not found literally in the passages cited. They express their general meaning and belong to the holy Apostle as a heading for the prophetic sayings gathered together.
Understood in this way, the word “righteous” must be given a broad meaning: righteous in everything, both before God and before men. By contrast, “unrighteous” likewise means unrighteous in everything, before God and before men.
Therefore in “there is none righteous,” one should not see the thought that someone sometimes sins or is sometimes unrighteous. The thought is that he is entirely sunk in unrighteousness.
He devises nothing and does nothing except unrighteousness. And all are such, without any exception.