Musnad Ahmad 135:1

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Sayyar and Yahya ibn Sa'id al-Qadi, that they both heard 'Ubadah ibn al-Walid ibn 'Ubadah narrating from his father. As for Sayyar, he said: From the Prophet, peace and blessings of Allah be upon him. And as for Yahya, he said: From his father, from his grandfather, who said: "We pledged allegiance to the Messenger of Allah, peace and blessings of Allah be upon him, to hear and obey in our hardship and our ease, in our willingness and our unwillingness, and even when preference is given over us, and that we shall not dispute the command with those who hold it, and that we shall uphold the truth wherever we are, and that we shall not fear, for the sake of Allah, the blame of any blamer."