It was God’s will to make Israel His special nation through which He would send the Messiah and which He would bless uniquely. It was not for their goodness or greatness but for His glory that he did it, and even Israel’s great sins would not lead God to forsake them as a nation or forgo to complete His great purposes for them.
And we pray:
O Lord, You have chosen and called out Your Church from the world for Your own glory. You chastise us when we sin, but You will not forsake us, for You will accomplish Your purposes in us and through us for Your own glory. Even so, Lord, let it be! Amen.