מדרש אויף משלי 21:15

A Psalm of David, when he fled from Absalom his son. This is what the Scripture says (Proverbs 21:15), "It is joy to the righteous to do justice." It is joy to the Righteous One of the world when He executes justice, for He is exalted in the world, as it is said (Isaiah 5:16), "But the Lord of hosts is exalted in judgment." Another interpretation: It is joy to the Righteous One of the world when He executed judgment in His house and destroyed it, as it is said (Psalms 68:36), "Awesome is God from His Sanctuary." Rabbi Yochanan said: If He did this to His Sanctuary, how much more so would He not show favor to others? Another interpretation: It is joy to the Righteous One of the world when the attribute of justice cleanses them from their iniquities. You can learn this, for David was struck by the attribute of justice, yet he began to rejoice and sing, saying, "A Psalm."

Psalm of Asaph. O God, nations have entered Your inheritance. And if this psalm was meant to be a lament. Similarly, you say (2 Samuel 15:30) "David went up the ascent of the Mount of Olives, weeping as he went." Yet it is written "psalm". This is what the verse means (Proverbs 21:15) "It is joy for the righteous to do justice." The righteous pay their debt and sing to God. Similarly, Asaph says "Psalm of Asaph, O God." It is like a king who had a son who was difficult and did not listen to his father. What did the king do? When he was angry, he entered his son's chamber and tore and cut until it was all ripped apart and threw the son out. The king said, "I did wrong by tearing my son's chamber. I could have done it better, and I did not kill him in my anger because if I did, my brother's son would inherit me, and it is better that my son inherits me." Similarly, Asaph said that God did wrong by releasing his anger on trees and stones and not on his children. As it says (Lamentations 4:11) "The Lord has exhausted His anger; He has poured out His blazing wrath." How has He kindled a fire in Zion? Therefore, Asaph said, "You let them enter, and it is not written in the Torah (Numbers 1:51) 'But the outsider who comes near shall be put to death.' Not only the outsider, but also Aaron's holy sons who entered to offer were burned. Similarly, "And so did Uzziah not enter except for your honor, to burn incense before you, and he came out as a leper, and not only that but the earth trembled. And these uncircumcised ones who signed to enter, God said to him, "These entered without permission, therefore I struck them down. But those who entered with permission, I commanded them to enter as it says, 'Behold, I am calling to all the families of the earth' (Jeremiah 1:15)." God said, "What did the name Jerusalem do? It made itself a ruin, but I will renew it as it says, 'Instead of bronze I will bring gold' (Isaiah 60:17)." He said before Him, "Master of the universe, behold, You are renewing these, Your sons who were killed. What will You do, as it says, 'They gave the corpses of Your servants as food to the birds of the sky, the flesh of Your pious ones to the beasts of the earth' (Psalms 79:2)? Were they pious? But isn't it written, 'Jerked horses and eager warriors, every man staring ahead to the fight, jeering at them' (Jeremiah 6:23)?" Asaph said, "Once judgment was passed on them, they were pious." And similarly it says, 'If the wicked son deserves a beating, he is called your brother before you afflict him' (Deuteronomy 25:2). At first, he is called wicked, and after he is punished, he is called your brother, as it says, 'And your brother was humbled before your eyes' (Deuteronomy 25:3)."