Romans 9:14-17 God's Responsible Love is the Source of His Righteousness
What shall we say then? Is there unrighteousness with God? Certainly not! For He says to Moses, "I will have mercy on whomever I will have mercy, and I will have compassion on whomever I will have compassion." So then it is not of him who wills, nor of him who runs, but of God who shows mercy. For the Scripture says to the Pharaoh, "For this very purpose I have raised you up, that I may show My power in you, and that My name may be declared in all the earth."
(Romans 9:14-17 NKJV)
Is God unrighteous? No, of course not. But why is He not unrighteous? Or to ask it in a positive way - why is God righteous?
God shows His mercy and compassion (which are forms of His love) to whom He desires. Therefore, mercy, compassion, and thus love are the reasons why He is righteous. God is righteous because He loves. Righteousness is a result of God's love. God can show that He is right and He can lead people in the right direction in life because He knows how to properly love.
This ability to point people in the right direction (righteousness) is tied to God's sovereignty or His authority and power. God's authority and power are based on the precept that God chose to love.
What does this mean?
God did not have to love anyone. God was not obligated to love anyone. God was and is God. God is all powerful and has ultimate authority. However, He chooses to love. Why did God choose to love? Because love was and is part of God's nature.
God showed His love, not because He favored a person. God showed His love (or refused it in the case of Pharoah) to teach the world that He is the God that people should come to in their lives. God showed His love on some so that other can see that there is a God who loves.
Most people have no idea that God loves them. They only know of a God to whom they are expected to submit. The God of the Bible wants to reach those people.