Would you please explain Romans 9:18?
Romans 9:18 states, "Therefore hath he mercy on whom he will have mercy, and whom he will he hardeneth." The context of this particular passage is in the midst of Paul's expressed desire for the salvation of the Jewish people. He says in Romans 9:3, "For I could wish that myself were accursed from Christ for my brethren, my kinsmen according to the flesh." Paul wanted them to be saved and he wished that this could be done even if it meant he himself being forever cursed. However, that was not God's will for salvation. As such, it is up to God as to how men are going to be saved. This is the discussion that he enters into in this particular chapter.
Notice he says in verse 6, "not as though the word of God hath taken none effect." The word of God had indeed said that Israel was going to be saved. Paul makes note of this in Romans 11:26, 27. However, who is Israel? He says in Romans 9:6, 7. Those who are of the seed of Abraham are the TRUE Israel--spiritual Israel. He explains this in verse 8 that just because one is the child of Abraham in the flesh doesn't mean that he is the child of Abraham according to promise. Those are two different things. Who are the children of promise according to Galatians 3:16? "Now to Abraham and his seed were the promises made. He saith not, and to seeds, as of many; but as of one, and to thy seed, which is Christ." Christ is the seed through which all nations would be blessed. So if the Jews in the time of Paul wanted to be saved, they must be saved through Christ, just as the Gentiles must be saved.
Paul says that this is illustrated through the cases of the birth of Isaac and Jacob. Both of these children were born as a result of promise, not as a result of lineage. That is, God promised that Abraham would have a son. Isaac was born through that promise. God also promised that Jacob would be the head of the house over Esau and Jacob became the child of blessing. It was through the promise of God that these things happened, not because of lineage. The Jewish people of that day believed that they would be saved based merely upon being the offspring of Abraham. They believed that their salvation was in their physical lineage. But Paul makes it clear that this was not the case. It is not lineage, but promise that affords one's salvation.
Paul then takes up in verse 14 the hypothetical objection that God might be unrighteous because some have thought that they ought to be saved on account of the lineage. After all, this is what they understood God to be promising. But Paul answers this by showing that just because these Jews had this understand of Godís promise does not necessarily imply that God is unrighteous. This is where the verse that we take up comes under consideration. Paul cites Exodus 33:19. He says that God will have mercy upon whom he will have mercy. What does this mean? It means that God is sovereign. It means that God is ultimately the one who decides what he means, not us. We must listen to His word and do His will in order to be saved. The result is that those who are saved will not be saved of their own power (Romans 10:2, 3), but by the power of God and the will of God (Romans 1:16, 17). He is the one to whom we must submit if we are going to have salvation in our life. This is true for the Jew as well as the Gentile. Paul uses Pharaoh as an example in this regard. Was Pharaoh lost because it was God's will that Pharaoh be lost? No, but because Pharaoh made the choice not to serve God and be obedient to him. God knew that when he put Pharaoh in the circumstance that he did, that Pharaoh would choose the way he did; so the scripture says that God hardened Pharaoh's heart. But Pharaoh chose his own destiny. It is through that means that Pharaoh's heart was hardened. Hence, God has mercy upon whom he will and hardeneth whom he will.
This mercy and hardening is not done merely through some arbitrary decision that God makes. It is always just; it is always righteous; it is always in keeping with the decisions that men make, but it is based upon God's will first and if we turn against God's will, then God hardens us. If we accept God's will, then God has mercy upon us. This is exactly the situation that the Jewish people were in during the time that Paul wrote the book of Romans. So within the context, the statement means that God has mercy upon whom he will and those whom he has willed to have mercy are those who accept the gospel. God will harden whom he will and those who he has hardened are those who have refused to accept the gospel.