Is there injustice on God's part?
What shall we say then? Is there injustice on God's part? By no means! For he says to Moses, “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.” So then it depends not on human will or exertion, but on God, who has mercy. For the Scripture says to Pharaoh, “For this very purpose I have raised you up, that I might show my power in you, and that my name might be proclaimed in all the earth.” So then he has mercy on whomever he wills, and he hardens whomever he wills. -Romans 9:14-18 ESV
Have you ever compared yourself to another and questioned why they seemed to be more blessed than you? I have. Occasionally I will see a couple walking together holding hands and recall the times before Ann was disabled when we were able to walk together. There is a wondering in that thought about the fairness of life and sometimes that sort of thinking can bleed into our spiritual life - and we subconsciously blame God for the the things that we deem as unfair.
In this passage Paul takes a stab at interpreting this image of fairness that we all struggle with. The story of Pharaoh illustrates the way that hearts are so often hardened. Certainly there was opportunity for him to experience mercy when he first heard the word of the Lord spoken by Moses. Yet each time he rejected God he hardened his heart a bit more. Eventually mercy seemed unobtainable to Pharaoh. It reminds me how easy it is for a heart to become hard.
Your mercy is new each morning. Teach us how to keep our hearts soft and open to that mercy.