43:21 This people I have formed for Myself;
They shall declare My praise.
Before we get into the rebuke of Judah (Jacob), we need to establish something that is still a huge point of confusion to this day. God did not look down from heaven and randomly choose the Jewish nation. He didn't purposely choose her either. He built Israel from nothing. It was a nation built, not on bloodlines, but on faith and promises. Abraham believed and that faith set him apart from his family. Isaac was a promise given, not an accomplishment realized. Jacob continued the line while Esau went s different direction and became in his descendants a separate nation. It was not genetics that built this nation. It was individuals who responded by faith to the calling of God on their lives. This is why Jesus could look bloodline Jews in the eye and tell them they weren't Abraham's children. It's why He could say that God could raise up children for Abraham from anywhere. It's why Paul could write that in Jesus there is no Jew or Greek. There is only belief and unbelief. Those who believe regardless of heritage, language, country of origin etc... are children of Abraham and heirs according to all the promises.
Do not allow yourself to get sucked into the growing movement in Christian circles that the genetic nation of Israel is elite, or above, or special in some way over the rest of humanity. It was this false view of themselves that lead them into pride, arrogance, and eventually into sending Jesus to the cross. God is no respected of persons. He has no favourites. He spent His ministry crossing borders and barriers of every kind to make that singular point. Seven times, the number of completeness, the book of Revelation describes or points to the full participation of the whole world in the controversy between good and evil. The message is for every kindred, tongue, nation, and people. We have one choice. There are but two sides. To believe and be transformed from Jacob (sinner) to Israel (overcomer) or to not believe and remain as we are.
Why would we choose the latter ever? Choose you this day. Today is the day of salvation.