John Wesley on Romans 1:17

The righteousness of God - This expression sometimes means God's eternal, essential righteousness, which includes both justice and mercy, and is eminently shown in condemning sin, and yet justifying the sinner. Sometimes it means that righteousness by which a man, through the gift of God, is made and is righteous; and that, both by receiving Christ through faith, and by a conformity to the essential righteousness of God. St. Paul, when treating of justification, means hereby the righteousness of faith; therefore called the righteousness of God, because God found out and prepared, reveals and gives, approves and crowns it. In this verse the expression means, the whole benefit of God through Christ for the salvation of a sinner. Is revealed - Mention is made here, and Rom 1:18, of a twofold revelation, - of wrath and of righteousness: the former, little known to nature, is revealed by the law; the latter, wholly unknown to nature, by the gospel. That goes before, and prepares the way; this follows. Each, the apostle says, is revealed at the present time, in opposition to the times of ignorance. From faith to faith - By a gradual series of still clearer and clearer promises. As it is written - St. Paul had just laid down three propositions: Righteousness is by faith, Rom 1:17: Salvation is by righteousness, Rom 1:16: Both to the Jews and to the gentiles, Rom 1:16. Now all these are confirmed by that single sentence, The just shall live by faith - Which was primarily spoken of those who preserved their lives, when the Chaldeans besieged Jerusalem, by believing the declarations of God, and acting according to them. Here it means, He shall obtain the favour of God, and continue therein by believing. Hab 2:4