The Messenger of Allah ﷺ commanded him to equip an army, but the camels were insufficient. So he commanded him to keep back the young camels of sadaqah, and he was taking a camel to be replaced by two when the camels of sadaqah came.  

أَنَّ رَسُولَ اللَّهِ ﷺ أَمَرَهُ أَنْ يُجَهِّزَ جَيْشًا فَنَفِدَتِ الإِبِلُ فَأَمَرَهُ أَنْ يَأْخُذَ فِي قِلاَصِ الصَّدَقَةِ فَكَانَ يَأْخُذُ الْبَعِيرَ بِالْبَعِيرَيْنِ إِلَى إِبِلِ الصَّدَقَةِ