They discussed this matter with Abu Bakr...

They discussed this matter with Abu Bakr, pressuring him a great deal to endorse their idea of cancellation, in spite of witnessing all the emphasis the Prophet (pbuh) had placed on rushing the mission, having heard his statement stressing that they should expedite sending the troops in a way too fast to allow the enemy to know about it, spending so much effort raising the army personally, appointing Usamah to take charge of it, and tying its flag with his own hands, saying: "Tomorrow, by the blessing of Allah, the Exalted One, leave early in the morning," till he died, as you have come to know.

Had it not been for the newly appointed successor of the Prophet (pbuh), they would have all decided to cancel the campaign and untie the flag's knot, but the caliph [Abu Bakr] refused to do so, and when they saw him determined to carry on the mission, ‘Umar approached him and requested him on behalf of the Ansar to depose Usamah from the post of the army's leader and appoint someone else.

It was not long since they had angered the Prophet and annoyed him by their displeasure with his appointment of Usamah as the commander of the regiment, nor since his going out of his house for the same reason, painfully feverish, bandaged, wrapped in a blanket, unable to walk steadily, his legs hardly carrying him due to the pain from which he was suffering; having ascended the pulpit, breathing heavily, fighting his pain, he said: "O people!

It has come to my knowledge that some of you have felt uneasy about my appointment of Usamah [as the commander]. If you cast doubts about his appointment, you had done so before when I appointed his father who, by Allah, was worthy of such an authority, and so is his son after him." Thus did he, peace be upon him and his progeny, emphasize, by swearing by Allah, that they should submit to what he had decreed. They did not.

The new caliph [Abu Bakr] refused to yield to their pressure to remove Usamah from his post. He leaped and took ‘Umar by the beard saying: "May your mother lose you, and may she be deprived of you as a son! He has been appointed by the Messenger of Allah (pbuh) and you still ask me to depose him?!"[^5] They reluctantly dispatched Usamah's regiment.

The total number of his troops was no more than three thousand, including one thousand cavaliers.[^6] It was dodged by many of those who had been drafted by the Messenger of Allah (pbuh) himself.