Musnad Ahmad 30:2339

Fazara ibn Umar narrated to us, he said: Fulayh informed us, from Suhayl ibn Abi Salih, from his father, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) went out on a military expedition he was undertaking. The Muslims ran out of provisions during it and were in need of food, so they asked the Messenger of Allah (peace and blessings of Allah be upon him) for permission to slaughter their camels, and he gave them permission. This reached Umar ibn al-Khattab, so he came and said: "O Messenger of Allah, their camels carry them and convey them to their enemy; will they slaughter them? Rather, O Messenger of Allah, call for the remnants of the provisions, then supplicate to Allah, the Mighty and Majestic, for blessing in them." He said: "Yes." He said: So he called for the remnants of the provisions. The people came with what remained with them, and he gathered it. Then he supplicated to Allah, the Mighty and Majestic, for blessing in it, and he called them with their vessels, and he filled them, and much remained over. The Messenger of Allah (peace and blessings of Allah be upon him) said at that: "I bear witness that there is no god but Allah, and I bear witness that I am the servant of Allah and His Messenger. Whoever meets Allah, the Mighty and Majestic, with these two, without doubting, will enter Paradise."