It should be obvious, but because God is so much greater than us in every way, we cannot fully understand all He does or why He does it. In the same way that small children have no real understanding of global economics, but they trust food and clothing will be provided, so we cannot grasp how God is bringing all things together for our good (Romans 8:28) under Christ (Ephesians 1:10). So these verses may seem strange to us. How can God choose one person and reject another and be a just God?
God has the right to give whatever He wants to whoever He chooses - because He is God. His choice does not depend on our goodness or badness; only His decision. And He is 100% about everything He does, love or hate. Out of a huge family tree, God chose one small line to be the human ancestry of our Lord Jesus Christ, which meant that all the others were excluded. However since Jesus, all those who believe in Him will be saved (John 3:16) ... so even those who were not in Jesus' human family tree, can be included in His future spiritual family.
Israel was supposed to be the showcase of God's truth and light to the world: but they failed. They were also the human ancestors of Jesus: and He did not fail! His appointment was to keep God's law perfectly, and become the spotless sacrificial lamb, dying for the sins of the whole world. However, the Jews in Rome still thought they were something special because of their religious background; but that could not save them. They needed Jesus, and Jesus alone. So do we! No amount of religious knowledge or pious ritual can save us if we have not received Jesus personally. Even pagan sinners are not barred from God, if they welcome Jesus! If you know Him, you can introduce anybody to Him ... whatever their religious background ... because God chooses that whoever receives Jesus will be given the right to be in His family (John 1:12 & www.crosscheck.org.uk).
© Dr Paul Adams