Ibn Hibban

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: A prophet (peace be upon him) was about to go out for battle, so he said to his people: No one should go with me who has married a woman and now wishes to bring her home, or who has built a building but has not yet put a roof on it, or who has bought a goat and is waiting for it to give birth. When the time for Asr came, or close to it, they came near the place of worship and he said to the sun: You are also under command and I am also under command. O Allah! Hold it back for me for a little while (from setting), so it was held back until Allah granted them victory. The spoils of war they obtained were gathered so that fire would come and consume it, but the fire did not consume it. So he said: There has been a breach of trust among you. Let one person from each tribe pledge allegiance to me. So the pledges began, and the hand of one man stuck to his hand. The prophet said: The breach of trust is in your (tribe). Let your tribe pledge allegiance to me. When his tribe pledged allegiance, the hands of two (the narrator is unsure, or perhaps three) individuals stuck to his hand. He said: You have committed the breach of trust. So they brought out a golden head of a cow and placed it among the spoils of war, which was lying in an open field. Then the fire came and consumed it. (The Prophet, peace and blessings be upon him, said) Before us, spoils of war were not made lawful for anyone. The reason is: When Allah saw our weakness, He made it pure (i.e., lawful) for us.