It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) dug the trench (khandaq), and his (peace and blessings be upon him) Companions had tied stones to their bellies because of hunger. When the Prophet (peace and blessings be upon him) saw this, he said: "Do you know of a man who could feed us a meal?" A man said: Yes. He (peace and blessings be upon him) said: "Well then, go ahead and guide us to him." So they went to the man, and he was in the trench digging his share. His wife sent word to him: Come, the Messenger of Allah (peace and blessings be upon him) has come to us. The man came running and said: May my father and mother be sacrificed for you - and he had a she-goat with her kid. He rushed towards it, and the Prophet (peace and blessings be upon him) said: "The kid (slaughter it; leave the goat) behind us." So he slaughtered the kid, and the woman took her flour, kneaded it and baked bread, and when the pot was ready she crumbled the bread into her bowl and poured the broth over it (tharid), and brought it near to the Prophet (peace and blessings be upon him) and his (peace and blessings be upon him) Companions. The Prophet (peace and blessings be upon him) put his finger in it and said: "Bismillah. O Allah, bless it. Eat." So they all ate from it until they were full, and they had eaten only a third of it, while two thirds remained. Then he (peace and blessings be upon him) sent away the ten men who were with him: Go and send to us the same number as yourselves. So they left, and another ten men came in their place and ate from it until they were full. Then he (peace and blessings be upon him) stood up and supplicated for the lady of the house, and prayed for blessing for her and for her household. Then they all walked to the trench, and he (peace and blessings be upon him) said: "Take us to Salman." There was a rock in front of him which they were failing to break. The Prophet (peace and blessings be upon him) said to his Companions: "Leave it to me, so that I am the first to strike it." So he (peace and blessings be upon him) said "Bismillah" and struck it, and a third of it broke off. He (peace and blessings be upon him) said: "Allahu Akbar! By the Lord of the Ka'bah, the palaces of Rome!" Then he struck it again and another piece fell, and he said: "Allahu Akbar! By the Lord of the Ka'bah, the palaces of Persia!" At this the hypocrites said: We are digging a trench to protect ourselves, and he promises us the palaces of Persia and Rome!
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12000