God’s mercy, along with His plan and will, are perfect. When He decides to have mercy it is for His purpose and for His glory, not ours. In Romans 9:18 Paul reiterates his quot of Exodus 9:16 in Romans 9:14, Therefore God has mercy on whom he wants to have mercy, and he hardens whom he wants to harden. It is God’s will that matters, not our understanding of why He chooses to do anything. We are to be thankful He has chosen us to be in His will and to be used for His service. Our ability to comprehend the full picture of God’s plan is not possible. We must trust, obey, and have faith in His love and perfect plan for us.