Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: When the Prophet (peace and blessings be upon him) set out for Banu Qurayzah, he went out riding a donkey, and with him was Sayyiduna Jibril (peace be upon him), riding a white mule, under him a cloth made of brocade (istabraq) set with pearls. He said: "O Muhammad! By the One who sent you with the truth, I will not go back from there until it is conquered for you, and I will crush them as an egg is crushed upon a rock." Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: He did not go back until that territory was conquered.
Al-Tabarani recorded it from his teacher Miqdam bin Dawud, who is da'if (weak).