In the words of verse 2 of the song I quoted here.
“Mercy is when God does NOT give us what we deserve!”
As I have mentioned before in these posts, all human beings have sinned. That means that what we do deserve is God’s punishment. His mercy means that he does not give us that punishment. However, that does not mean that he totally ignores sin – his character demands that it be punished.
That’s where Jesus comes in. On the cross, he was punished so that we do not need to be. If we will put our trust in him, we do not have to face his punishment – separation from him for ever. But we do need to take that step, forgiveness does not come by default.
Let’s be grateful for God’s mercy – he does not give us what we deserve. And we thank him for Jesus whose death on our behalf was an act of God’s mercy.