“For the horses of Pharaoh with his chariots and his horsemen went into the sea, and the Lord brought back the waters of the sea on them, but the sons of Israel walked on dry land through the midst of the sea” (Exodus 15:19, NASB).
You might notice in this verse from the Song of Moses, which proclaims God’s greatness in helping Israel escape from Egypt, that the same miracle that God used to deliver the Israelites is also the same miracle that God used to destroy Pharaoh’s army!
“And what if God, desiring to display His wrath and to make His power known, endured with much patience objects of wrath ready for destruction. And what if He did this to make known the riches of His glory on objects of mercy, that he prepared beforehand for glory–on us, the ones He also called, not only from the Jews but also from the Gentiles?” (Romans 9:22-24, HCSB).
These verses do not mean that God desires to show His wrath on those who deserve it. Rather, they mean that God desires to show His mercy by saving those who deserve His wrath. And, God can best show His love by having mercy on those who deserve His wrath.