Romans 9:14-18

So, what does all this mean? Are we saying that God is unfair? Of course not! He had every right to say to Moses: “I will be merciful to whomever I choose and I will show compassion to whomever I wish.” Again, this proves that God’s choice doesn’t depend on how badly someone wants it or tries to earn it, but it depends on God’s kindness and mercy. For just as God said to Pharaoh: “I raised you up as ruler of Egypt for this reason, that I might make you an example of how I demonstrate my miracle power. For by the example of how I deal with you, my powerful name will be a message proclaimed throughout the earth!” So again we see that it is entirely up to God to show mercy or to harden the hearts of whomever he chooses.