What is the meaning of Romans 1:16-18?

16 For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek.17 For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith.18 For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness; (Romans 1:16-18 KJV)

Thomas Haweis

Verses 16-18: The apostle having experienced the power of the gospel on his own soul, so far was he from being ashamed of the reproach of the cross, which to the Jews was a stumbling block, and to the Greeks foolishness, that he gloried in the honour of being sent to publish to small and great the glad tidings of salvation though a crucified Jesus; and he gives his reasons for so doing.

1. Because the gospel which he preached was  the power of God unto salvation to every one that believeth, to the Jew first, and also to the Greek; this being the great mean God is pleased to make use of, which, through the Spirit’s effectual working, comes with demonstration to the sinner’s heart; and it was sent to the Jews first, and then more generally to the Gentile world, that as many of both as were ordained unto eternal life, might believe the divine report, and by faith embrace and lay hold of the hope of eternal life revealed in the gospel: for therein is the righteousness of God revealed, that transcendently glorious righteousness which God the Son incarnate hath wrought out for us, and God the Father, according to the tenor of the everlasting covenant of grace, hath appointed as the condition of our salvation, hath declared his acceptance of, by the resurrection of Jesus, and imputes to our account; and which is set forth in the gospel, as the great object of our faith, the meritorious cause of our justification, and our title to eternal glory: from faith to faith, being wholly of faith, exclusive of all works and duties of our own, (see Ro 6:12; 2Co 3:18) or from the doctrine of faith in the word, to the grace of faith in the heart; or rather from one degree of faith to another, as we gain clearer discoveries of the fullness, suitableness, and transcendent glory of that finished salvation which is revealed to us in the gospel. As it is written, in the Old Testament, which exactly corresponds in doctrine with the new, The just, or justified man, shall live by faith; hereby he is brought into, and continues in, a state of spiritual life; so that death, the wages of sin, can have no more dominion over him; and, being regarded in God’s sight as righteous and just, he possesses a title sure and indefeasible to that eternal life which is brought to light in the gospel, as the reward of the Redeemer’s obedience unto death, even the death of the cross.

2. Because, without this method of gospel grace, every human creature must lie down under eternal wrath and despair: for the wrath of God is revealed from heaven against all ungodliness, and unrighteousness of men, who hold the truth in unrighteousness, God’s word denounces vengeance on every transgressor; his judgments past have often fearfully spoken his displeasure against sin; and the whole world is found guilty before him, since all have sinned in opposition to their better knowledge, whether Jews, who enjoyed the light of revelation, or Gentiles, whom God left not without witness, giving them sufficient traditionary notices of his being, perfections, and attributes, which the visible objects around them served to explain, so as to leave them without excuse in their idolatry and disobedience. Note, (1.) Every sinner at God’s bar will stand self-condemned; he will be made to own he knew better, and did worse. (2.) Fearful is the wrath revealed against all ungodliness and unrighteousness of men: if it once seize on the sinner, it will burn, and never can be quenched. (3.) How highly should we value, and how eagerly embrace, that glorious gospel, which alone can afford us shelter from those terrible blasts of the divine vengeance!