Therefore God has mercy on whom he wants to have mercy, and he hardens whom he wants to harden.Romans 9:18 NIV
The sovereignty of God, especially concerning our salvation, can lead to contentious debate. And this verse, as well as the surrounding passage, is often used by one side of the debate to prove their position that God sovereignly chooses some people and rejects others solely according to his own will. Others will point to passages like Romans 9:30-32, which immediately follows this one, to argue for the importance of faith in salvation.
So, is a person saved by faith in Christ? Or because God sovereignly choose them? It seems to me that the answer to both of these questions is yes. Scripture clearly teaches God’s absolute sovereignty, including who will be saved. I do not know any other way to understand this passage. But throughout the New Testament, we are told that salvation is an act of God’s grace received through faith. Salvation comes to all who have faith in the work of Christ on our behalf.
One of the awesome things about God is that he is beyond our comprehension. God’s sovereign choice in who will be saved and our free choice to respond to him in faith may seem to us to be at odds. But just because we may not understand it does not negate its truth. I can whole-heartedly affirm God’s sovereign choice in my salvation while also affirming the role of faith. God sovereignly chose me. And I freely chose to respond to his offer of salvation. Do I fully understand how to resolve those two seemingly contradictory positions? No. But I don’t have to. I am satisfied in knowing that what is a mystery to me is not to God.