And it is narrated from him that the Messenger of Allah (peace and blessings be upon him) ordered him to equip an army, but the camels ran out, so he ordered him to take from the camels of the alms. He said:

The Shaykh :"And it is narrated from him—meaning from 'Abdullah ibn 'Amr—:

The Prophet (ﷺ) commanded him to equip an army. Then, when the camels were insufficient, he commanded him to keep back the young camels of Sadaqah. He said, "I was taking a camel to be replaced by two when the camels of Sadaqah came."

أن النبي الله صلى الله عليه وسلم أمره أن يجهز جيشاً ، فنفدت الإبل ، فأمره أن يأخذ على قلائص الصدقة ، قال : فكنت آخذ البعير بالبعيرين إلى إبل الصدقة

Bulugh al-Maram 7:74

Al-Hakim and al-Bayhaqi narrated it, and its narrators are trustworthy":
His statement: , means: to manage the affairs of the army, purchase its necessities, and dispatch it. An army is a group of soldiers exceeding four hundred.
And his statement: means the camels prepared for jihad ran out and were exhausted. : Qalā'is is the plural of qalūs, which is a she-camel. It was attributed to alms because it is collected from the wealth of the people of camels and brought to Madinah, so he ordered him to take from the camels of the alms.
He said: : Do I take one camel for two as a loan or as a purchase?
The student: As a purchase.

The Shaykh : As a purchase, definitely as a purchase, because the preposition "ba" here indicates exchange, and it is known that riba (usury or interest) is not permissible for a person to give one and take two, because it would be riba, because it is a loan that brings benefit, and that is riba.
And his statement: means: until the camels of the alms arrive.