When there is not enough to go round
Their provisions had run out and they asked permission to slaughter their riding camels.
أَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ، وَأَنِّي رَسُولُ اللَّهِ
He called for what remained of their provisions, gathered it on a mat, asked for blessing over it, then told them to bring their vessels. Every vessel in the army was filled, and they ate until they were satisfied, and there was still some left.
ʿUmar had advised gathering what was left rather than slaughtering the camels they still needed to ride home on.
The full narration
Narrated Salama:Once the journey-food of the people ran short and they were in great need. So, they came to the Prophet to take his permission for slaughtering their camels, and he permitted them. Then `Umar met them and they informed him about it. He said, "What will sustain you after your camels (are finished)?" Then `Umar went to the Prophet (ﷺ) and said, "O Allah's Messenger (ﷺ)! What will sustain them after their camels (are finished)?" Allah's Messenger (ﷺ) said, "Make an announcement amongst the people that they should bring all their remaining food (to me)." (They brought it and) the Prophet (ﷺ) invoked Allah and asked for His Blessings for it. Then he asked them to bring their food utensils and the people started filling their food utensils with their hands till they were satisfied. Allah's Messenger (ﷺ) then said, "I testify that None has the right to be worshipped but Allah, and I am His Apostle
Source
Ṣaḥīḥ al-Bukhārī · 2982
- Agreed upon as authentic (al-Bukhārī / Muslim)