Romans 9:16-18
9:16 So then, it does not depend on human desire or exertion, but on God who shows mercy.
9:17 For the scripture says to Pharaoh: “For this very purpose I have raised you up, that I may demonstrate my power in you, and that my name may be proclaimed in all the earth.”
9:18 So then, God has mercy on whom he chooses to have mercy, and he hardens whom he chooses to harden.