Its chain of transmission is weak.

‘Umāra ibn ‘Ammār ibn Abī al-Yasar al-Sulamī narrated, from his father, from his grandfather:
“I saw al-‘Abbās on the Day of Badr. He was standing motionless, as if he were an idol, while tears streamed from his eyes. I exclaimed, ‘May Allah repay you—though you are kin—with evil! Will you fight your nephew at the side of his enemy?’

He answered, ‘What has happened—has he been killed?’

I said, ‘Allah has granted him greater might and fuller support than that.’

He asked, ‘Then what do you want of me?’

I replied, ‘To take you prisoner, for the Messenger of Allah ﷺ has forbidden us to kill you.’

He said, ‘This is not the first time he has upheld the ties of kinship.’ So I captured him and brought him to the Messenger of Allah (1) ﷺ.

Al-Thawrī transmitted—from Abū Isḥāq, from al-Barāʾ, or someone else—who said:
“A man from the Anṣār brought al-‘Abbās, having taken him captive, but al-‘Abbās said, ‘This is not the one who seized me.’ The Prophet ﷺ said, ‘Allah has indeed supported you with a noble angel.’ (2)

Ibn Isḥāq reported—from someone who heard it from ‘Ikrima, from Ibn ‘Abbās—who said:
“Abū al-Yasar captured al-‘Abbās, and the Prophet ﷺ asked, ‘How did you take him prisoner?’ He replied, ‘A man helped me—one I had never seen before or after—who looked such-and-such.’ The Prophet said, ‘A noble angel assisted you against him.’ (3)

He then said to al-‘Abbās, ‘Ransom yourself, your nephew ‘Aqīl, Nawfal ibn al-Ḥārith, and your ally ‘Utbah ibn Jahdam. (4)’

But al-‘Abbās refused and said, ‘I embraced Islam before…”