"To David, may the Lord contend with my enemies. This is what the scripture says (Isaiah 51:21): "Therefore, listen to this, you afflicted one, made drunk, but not with wine." From what am I made drunk? From troubles, but not from wine.
Because they are standing against me and I have no one to fight for me except you. And so it says (Psalm 9:13): "For the avenger of bloodshed remembers them; He does not forget the cry of the afflicted." The assembly of Israel said, "If you do not stand for me, who will stand for me? Look at what they are doing to me."
And so it says (Lamentations 3:59-60): "You have seen, O Lord, their reproach and all their schemes against me. You have heard their taunts, O Lord, all their plots against me." "O Lord, my soul's champion, you have seen their insults, and their scheming against me." And so David says (Psalm 70:2): "May You be a refuge for me, O God."
Therefore, David said, "May the Lord contend with my enemies." It is possible for a person to say to his master, "Contend with my enemies, and go out and fight against me." But the Holy One, blessed be He, said to David, "Engage in Torah study, and I will fight your battle." And so Moses says (Numbers 21:14): "Therefore it is said in the Book of the Wars of the Lord: 'Waheb in Suphah and the wadis, the Arnon.'"
If you engage in Torah study, which is written in the book, I will fight for you. Therefore, David said, "May the Lord contend with my enemies."...