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. (Using translation from Abū Dāʾūd 3357)
أَنَّ رَسُولَ اللَّهِ ﷺ أَمَرَهُ أَنْ يُجَهِّزَ جَيْشًا فَنَفَدَتِ الْإِبِلُ «فَأَمَرَنِي رَسُولُ اللَّهِ ﷺ أَنْ آخُذَ مِنْ قَلَائِصِ الصَّدَقَةِ فَكُنْتُ آخُذُ الْبَعِيرَ بِالْبَعِيرَيْنِ»