What shall we say then? Is there unrighteousness with God? God forbid.  For He saith to Moses, “I will have mercy on whom I will have mercy, and I will have compassion on whom I will have compassion.”  So then it is not of him that willeth, nor of him that runneth, but of God that sheweth mercy.  For the Scripture saith unto Pharaoh, “Even for this same purpose have I raised thee up, that I might shew My power in thee, and that My name might be declared throughout all the earth.”  Therefore hath He mercy on whom He will have mercy, and whom He will He hardeneth.
Romans 9:14-18