It is natural that one should desire that his household would be saved. Paul had that same desire for his Jewish family. In their ignorance of His purpose, they had rejected Christ and were zealous toward their own traditions in the Law of Moses. He desired that they would redirect their zeal toward the proper knowledge that justification and salvation were through Christ and that the Law of Moses had ended.
We see many religious people today who are greatly zealous, but because of a lack of knowledge, they are promoting religious error. Those who have the truth of God should be as zealous as those who are teaching man-made error.
Paul stated that the person who wanted to live by the Law of Moses was obligated to do the whole law completely, which they were unable to do.
Those who would desire to see Christ come back from heaven or return again from the grave would not benefit because He had been rejected when those events did occur. To bring Christ back from the dead again would be useless because they still would not accept Him.
Paul said that the way to salvation was to believe with all one’s heart that God had raised Jesus from the dead and to confess that faith with the mouth. He reminded the Romans that salvation was available to both Jews and Greeks (Gentiles). Saving faith is one of obedience and action.
Man must hear the truth of the gospel before he can believe it. The first teachers were selected by God and given the message to teach. Today, man still must hear the word of God, but he hears through reading and being taught the word as written by men inspired by the Holy Spirit. Many, however refusing to obey give up their heavenly home.
Again, Paul quoted Old Testament prophecies that foretold the rejection of Christ by the Jews and the acceptance of Him by the Gentiles. Those prophecies were being fulfilled during that period in man’s history.