God is good, all the time. And all the time… God is GOOD! I think this is David’s sentiment here.
But take note here that only those who “call upon Him” are the ones who receive forgiveness and mercy. And what does it actually mean to “call upon” the Lord? It’s as simple as saying, “Lord, help! I need your forgiveness and mercy!”. After all, we have this eternal promises from God in Hebrews 4:
Therefore, since you now know that God is merciful to those you who humble themselves and draw near to Him, even when drawing near is to confess sin, take whatever steps are necessary in your life to receive forgiveness and be reconciled to God through Christ!