Midrasch zu Mischlej 25:8

Abaye said to R. Dimi: "How do the people of the West (land of Israel) explain this passage (Prov. 25, 8) Do not proceed to a contest hastily, lest [thou know not] what thou wilt have to do at its end, when thy neighbor has put thee to confusion. Carry on thy cause with thy neighbor; but lay not open the secret of another. And he answered thus: "At the time the Holy One, praised be He! said to Ezekiel (Ezek. 16, 3) And thou shalt say … thy father was an Emorite and thy mother was a Hittite, the arguing spirit (Gabriel) said before the Holy One, praised be He! 'Sovereign of the Universe! If Abraham and Sarah would have come and stood before Thee, and Thou wouldst have said this to them, they should become ashamed. Carry on Thy cause with Thy neighhor; but lay not open the secret of another.'" Had he then (Gabriel) a right to say such a thing? Yea! as R. Jose b. Chanina said: Gabriel has three names — Piskon, Itmon, Zigoron, Piskon, because he argues before Heaven for Israel's sake; Itmon, because he covers the sin of Israel; Zigoron, because after he concludes [his defence for Israel without effect] none [of the other angels] would reopen it."