"To the conductor upon the lilies, a testimony of David, to teach. This is what is said (Isaiah 50:8): 'Who will contend with me? Let us stand up together. Who is my adversary?
Let him come near to me.' The Holy One, blessed be He, gave the Torah to Israel to respond with it to all the nations. When Joab went to fight against Aram, they said to him, 'You are not the son of Jacob,' as the verse states (Genesis 31:42), 'And now, if you would take my daughters, beware of harming them; for if you do, no man is present with us; look to God as witness between you and me.' Then Jacob took a stone and raised it as a pillar.
When Joab heard this, he did not know what to do or how to answer. He went to David and said to him, 'This and that was said to me by the sons of Aram.' Immediately, the Sanhedrin, called 'Lilies', was convened. And so Solomon says (Song of Songs 7:3): 'Your belly is a heap of wheat, encircled with lilies.'
Our forefathers made two covenants, one made by Abraham, as the verse states (Genesis 21:23), 'Now swear to me here by God that you will not deal falsely with me or with my offspring or with my posterity, but according to the kindness that I have done to you, you will do to me and to the land where you have sojourned.' And so they made a covenant. When the Philistines came to enter the land, they said to them, 'You are not the seed of Abraham, and you do not observe the commandments of the covenant that Abraham made with Abimelech.'
They said to them, 'We do observe them,' and the Philistines went away. And so it says (Deuteronomy 2:23): 'The Avvim who lived in villages as far as Gaza, the Caphtorim who came from Caphtor, destroyed them and settled in their place.' They were protected by that covenant, and immediately they entered and possessed the land. And so when Aram said to Joab, 'You are not the son of Jacob,' Jacob made a covenant with Aram until this exile.
He said to them, 'But they did not come first,' as the verse states (Numbers 22:5), 'Behold, a people came out of Egypt; behold, they cover the surface of the land, and they are dwelling opposite me.' Not only that, but also in the days of Cushan Rishathaim, as it says (Judges 3:8): 'Therefore, the anger of the Lord was kindled against Israel, and He sold them into the hands of Cushan Rishathaim, king of Mesopotamia.'
They committed two transgressions, one in the days of Balaam, and one in the days of Cushan. Once they learned this from the Sanhedrin, Joab returned and said [to the Arameans], 'If I destroy them now, what will I do when I ascend from the war?'"