In love he predestined us to be adopted as his sons through Jesus Christ in accordance with his pleasure and will. Ephesians 1:5
In the Old Testament we find that God predestined the Israelites to be his people. “Out of all the nations you will be my treasured possession. Although the whole earth is mine, you will be for me a kingdom of priests and a holy nation. These are the words you are to speak to the Israelites” Exodus 19:5-6. However it was not enough to be chosen. They still had to exercise faith in God to be made righteous.
Paul writes in Galatians 3:8 “The Scripture foresaw that God would justify the Gentiles by faith, and announced the gospel in advance to Abraham: All nations will be blessed through you.” So although the Israelites were chosen to be God’s people it was God’s intention to bless all nations through them. They were to be his witness and his instrument of blessing. We see this often in the Old Testament. Ruth and Rahab were not Israelites but came to be included with God’s people; Jonah is sent to Nineveh and other prophets are sent to Egypt and Edom. Being predestined was never meant to exclude others.
In the New Testament the church is now God’s chosen people. “But you are a chosen people, a royal priesthood, a holy nation, a people belonging to God” (1 Peter 2:9). God has predestined the church and likewise it is God’s intention to bless all people through the church. The church is God’s body in the world to reach out to all people. Being predestined still doesn’t mean excluding others. Rather it should motivate us to fulfill God’s intention of the church being his witness and his instrument of blessing to the world.