Romans 1:17

For therein

(γαρ εν αυτω). In the gospel (verse Romans 1:16) of which Paul is not ashamed.A righteousness of God

(δικαιοσυνη θεου). Subjective genitive, "a God kind of righteousness," one that each must have and can obtain in no other way save "from faith unto faith" (εκ πιστεως εις πιστιν), faith the starting point and faith the goal (Lightfoot).Is revealed

(αποκαλυπτετα). It is a revelation from God, this God kind of righteousness, that man unaided could never have conceived or still less attained. In these words we have Paul's statement in his own way of the theme of the Epistle, the content of the gospel as Paul understands it. Every word is important: σωτηριαν (salvation), ευαγγελιον (gospel), αποκαλυπτετα (is revealed), δικαιοσυνη θεου (righteousness of God), πιστις (faith) and πιστευοντ (believing). He grounds his position on Habakkuk 2:4 (quoted also in Galatians 3:11). By "righteousness" we shall see that Paul means both "justification" and "sanctification." It is important to get a clear idea of Paul's use of δικαιοσυνη here for it controls the thought throughout the Epistle. Jesus set up a higher standard of righteousness (δικαιοσυνη) in the Sermon on the Mount than the Scribes and Pharisees taught and practised (Matthew 5:20) and proves it in various items. Here Paul claims that in the gospel, taught by Jesus and by himself there is revealed a God kind of righteousness with two ideas in it (the righteousness that God has and that he bestows). It is an old word for quality from δικαιος, a righteous man, and that from δικη, right or justice (called a goddess in Acts 28:4), and that allied with δεικνυμ, to show, to point out. Other allied words are δικαιοω, to declare or make δικαιος (Romans 3:24; Romans 3:26), δικαιωμα, that which is deemed δικαιος (sentence or ordinance as in Romans 1:32; Romans 2:26; Romans 8:4), δικαιωσις, the act of declaring δικαιος (only twice in N.T., Romans 4:25; Romans 5:18). Δικαιοσυνη and δικαιοω are easy to render into English, though we use justice in distinction from righteousness and sanctification for the result that comes after justification (the setting one right with God). Paul is consistent and usually clear in his use of these great words.