Verse 18 declares the immutable sovereignty of God in salvation and mercy. If God has the right and power to show mercy to whom He will, then "whom He will He hardeneth." The Scripture declares that Pharaoh hardened his own heart (Exod. 9:34-35). It also declares that God hardened his heart (Exod. 10:1). God is said to harden men's hearts (much like it is said, "God creates darkness and evil," Isa. 45:7) by leaving men to their own way, wisdom, and evil desires. If light is not given by God, darkness will reign. If the means of grace are not set forth, evil will abound (Acts 2:23). The same means that result in life and mercy to the elect become stumbling stones and means of greater condemnation to them that perish (II Cor. 2:15-16).
(Vs. 19) Here is the third objection to sovereign mercy held forth by the natural mind. The first objection (Verse 6)most of Israel perishes, so it seems the purpose and promise of God has failed. The second objection (Verse 14)God is unjust to choose some and pass by others. Now in Verse 19 we come to the third objectionif God shows mercy to some and none can resist His sovereign will, then why does He find fault with sinners? If the wrath of men is so under the control of God that it, too, serves His purpose, then why blame the sinner?
(Vs. 20-23) In these verses the apostle gives three distinct answers to this objection. These answers will not satisfy the natural mind, but they will be sufficient for every believer who receives the Word by faith.
(1)(Verse 20his first answer) "O man, who are you to dispute with God? Who are you to question God's providence or hope to understand God's ways? How foolish and arrogant for a finite creature to sit in judgment on God's mercy and justice: The answer to why God does what He does in found in Himself, not in our natural wisdom.
(2)(Vs. 21his second answer) The word "power" here denotes right, privilege, or authority. God has a right to do with His own what He will. But it is more than that. God's power is always exercised in a way that is consistent with His righteousness and glory. The chief end of man is to glorify God; therefore, God has the right to do what best serves His glory.
(3)(Verse 22his third answer) God has determined to make known to this universe two things. He will make known His wrath against sin, and He will make known the riches of His grace and glory.
God had endured these vessels of wrath with much patience as He did the OLD WORLD before the flood, PHARAOH before He cut him off, and SODOM before He destroyed it. These unbelievers have light which they hate and means of grace which they despise.
The vessels of mercy receive His mercy, love, and grace, not because they are better or wiser than others or because they deserve it, but because God chose to reveal His grace in them and make them objects of His mercy from eternity.
"It is not wise for the novice to meddle too much with Divine purposes and mysteries. Nothing has greater tendency to confound the understanding and to harden the heart than to take strong meat too early. Let us not talk of these matters too lightly. Hidden things belong to God; things that are revealed belong to us. Touching the Almighty we cannot find Him out; but He is excellent in power, judgment, and grace. He will not afflict without cause. Let us rejoice that the great truth of Divine grace is written in the Word and revealed in Christ." M. Luther.
(Vs. 24) The promise of eternal life was not made to the natural seed of Abraham but to the true seed of AbrahamCHRIST (and all who by grace are in Him, whether Jew or Gentile.)
(Vs. 25-28) The calling of the Gentiles is prophesied throughout the Old Testament. This prophecy is from Hosea 2:23. The Jewish nation was typically the spouse of God; but when the Christ shall come, He will reveal His true seed and call her beloved which was not belovedthat is, the Gentiles (Eph. 2:11-13).
Though the descendants of Abraham number in the millions, only a small number are the true Israel of God. These Jews thought that all of Abraham's descendants were the people of God. When the Messiah came and they rejected Him (John 1:10-11), after hundreds of years of long-suffering with their idolatry and rebellion, God made a short work of them and has blinded them to this day.
(Vs. 29) Actually the doctrine of election, very far from being a harsh and cruel doctrine, is a cause for rejoicing; for had it not been for God's choosing to save a people, neither Jew nor Gentile would escape the wrath to come. We would have ail been destroyed as Sodom and Gomorrah.
(Vs. 30-33) What is the result of all this discussion? The conclusion from the whole is that those Gentiles who are chosen of God, called by the Spirit, and redeemed by Christ have obtained the righteousness of Christ by faith (though they did not seek it and were abandoned to evil), while Israel (who had all the advantages, the Law and the prophets, and sought acceptance with God) found it not! Why? Because Israel sought righteousness by works and not by graceby the deeds of the Law and not by faith.
Israel stumbled at Jesus Christ. Instead of looking to Him (Who fulfilled all types, promises, and sacrifices), they rejected Him altogether. Had they understood their prophets, they would have embraced Christ. Therefore, they were offended by His words and were ashamed of His cross.