Children of the Promise
Religious people like to believe that, because of who they are and what they do, God will accept them. That is why they are religious! The Jews of Paul's day thought that as long they could claim direct descent from Abraham, then they were children of God. But Paul said, 'No'. God's promise to Abraham was received by faith (Romans 4:1-3). In the same way Abraham had two children, Ishmael as a result of his faithlessness and Isaac as a result of his faith. It is faith in God's promises which brings people into relationship with Him - in the same way that Abraham eventually believed the promise that his wife Sarah would have a child.
The Jews in Rome needed to grasp this. They were not part of God's family because of their human ancestry, but because of the spiritual bond created by the Holy Spirit (1 Corinthians 6:11). This happened when they believed the gospel and received Christ into their hearts by faith. And that was exactly the same way in which the Gentiles became children of God - even though they did not share the same historic family tree.
Paul's words to the Jews of his day speak to all of us - whatever our ethnic and religious background. God's promise never fails. He promises, "If you declare with your mouth, ‘Jesus is Lord,’ and believe in your heart that God raised him from the dead, you will be saved." (Romans 10:9) That applies to everybody! Revelation 22:17 says, "The Spirit and the bride say, ‘Come!’ And let the one who hears say, ‘Come!’ Let the one who is thirsty come; and let the one who wishes take the free gift of the water of life."
That is why we can be confident to share the gospel: God will honour His promise to everybody who believes in Jesus. He will make them His very own children (John 1:12). That is true irrespective of their age, gender, nationality, religious background, social status, wealth or intellect! So, tell somebody today that Jesus loves them and wants them to be saved.