How do we know God is sovereign over mercy?

In Romans 9:15-16, Paul clarifies that God has the sovereign right to show mercy on whom He chooses. This sovereignty confirms that mercy is not a matter of human will or exertion but is solely according to God's purpose and grace. It also signifies that our comfort is rooted in the assurance that God, as the 'Father of mercies,' is in control of all situations, demonstrating His loving kindness selectively as He knows what His people need. Hence, recognizing God’s sovereignty over mercy strengthens our faith during trials, knowing He acts for our good.