Musnad Abu Ya'la al-Mawsili 251:8

Muhammad ibn Bashar narrated to us, Muhammad ibn Ja’far narrated to us, Shu’bah narrated to us, from Ziyad ibn ‘Alaqah, who said: I heard Jarir ibn ‘Abd Allah when al-Mughirah ibn Shu’bah died and [someone] was appointed. I saw Jarir delivering a sermon, and he said: "I advise you to fear Allah alone, with no partner, and to listen and obey until an amir (leader) comes to you." He then mentioned al-Mughirah and said: "Seek forgiveness for him, may Allah pardon him, for he used to love well-being." Then he said: "As for what follows, I pledged allegiance to the Messenger of Allah (peace and blessings of Allah be upon him) upon Islam, and he stipulated upon me sincerity toward every Muslim. By the Lord of this mosque, I am indeed sincere toward you."