Most people can remember the anguish of realising that something precious has been thrown away.  It was not intentional, but careless.  Either it was accidentally thrown away along with other things, or it was carelessness because attention had been focussed somewhere else, or its value had not been understood at the time.  That was the Apostle Paul's concern for his own people, the Jews.  Salvation in Christ had been offered to them, but they did not recognise Jesus as the Saviour and threw away their promised salvation (Romans 10:1-4).

In explaining to the Gentiles, the privileges that they have in Christ by faith, Paul also wanted to stir his own people into realising that Jesus Christ was the promised Messiah.  Some of the Gentiles had understood and now valued Jesus very highly.  But Paul did not want his own people to miss the grace of God.  The root of faith had been planted in Israel.  New Gentile branches had been grafted in but he wanted Israelites to receive the new life of Jesus as well (Romans 11:24).

Paul was specifically writing about his missionary zeal for the Jews, and that remains a special concern for those who love Jesus.  However, the principle also applies to everybody who has had some background teaching in God's Word, been brought up in a Christian family, or even who have started to serve in the Christian church. It is right that believers should care about their family, friends and colleagues who have known about Christ, but have disregarded His value and separated themselves from His love. True hearted believers will painfully long that they will receive His grace they once heard about, even though they have now become careless and reject His promises. It is right to grieve over such people.

Do not stop speaking the truth to them. When they hear the true gospel message, some will want to turn and be saved (Romans 10:13-14).  It will take prayer and love, courage, conviction and sensitivity; but as you speak the truth some will turn to Jesus in repentance and faith.