Al-Mu'jam al-Awsat 835 — I was present with al-Hajjaj bin Yusuf while

Qudamah bin Ibrahim bin Muhammad bin Hatib al-Jumahi (may Allah have mercy on him) narrates: "I was present with al-Hajjaj bin Yusuf while he was beating Abbas bin Sahl bin Sa'd al-Sa'idi (may Allah have mercy on him) over the affair of Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with them both), when his father, Sayyiduna Sahl (may Allah be pleased with him), appeared wearing a waist-wrap and a cloak, and called out to al-Hajjaj: 'Do you not observe the instruction of the Messenger of Allah (peace and blessings be upon him) regarding us?' He asked: 'What did the Messenger of Allah (peace and blessings be upon him) instruct regarding you?' He said: 'He (peace and blessings be upon him) instructed that the good-doers of the Ansar be treated well and that their wrongdoers be pardoned.' So al-Hajjaj released him."
No one narrated this hadith from Qudamah bin Ibrahim (may Allah have mercy on him) except Abdullah bin Mus'ab (may Allah have mercy on him), and his son Mus'ab (may Allah have mercy on him) is alone in narrating it.