Moreover, he had prepared Usāma’s army before falling ill. Near the end of his life—may Allah bless him and grant him peace—he appointed Usāma commander over an army composed mostly of the Emigrants, among them Umar ibn al-Khattāb. They were (1) three thousand strong. He ordered him to raid the people of Mu'tah and the region of Palestine, where his father, Ja'far, and Ibn Rawāha had fallen.

Usāma ibn Zayd prepared for the campaign and went out with his baggage train to al-Jurf. He remained there for several days because the Messenger of Allah—may Allah bless him and grant him peace—was ill. The Messenger of Allah—may Allah bless him and grant him peace—then summoned Usāma and said:

“Set out in the morning with Allah’s blessing, victory, and well-being. Then raid (2) the place I commanded you to raid.”

Usāma said, “O Messenger of Allah, you are weak this morning, and I hope Allah will restore you to health. Allow me to remain until Allah heals you. If I depart while you are in this condition, I shall leave with a painful wound in my heart on your account, and I do not wish to have to ask others for news of you.”

The Messenger of Allah—may Allah bless him and grant him peace—gave him no answer. The Messenger of Allah—may Allah bless him and grant him peace—died several days later. When Abū Bakr assumed the caliphate, he sent Usāma forth with that army, except that he sought Usāma’s permission (3) for Umar ibn al-Khattāb to remain, since Umar was a man of sound judgment whose counsel served Islam well. Usāma granted him permission and then proceeded to the destination to which the Messenger of Allah—may Allah bless him and grant him peace—had ordered him to go. He inflicted a devastating blow on that (4) enemy; he and his companions took spoils, and he slew the man who had killed his father. Allah brought them safely back to Medina.