Sahih Bukhari | Volume 9 | Hadith Number 307

Narrated by 'Ubada bin As-Samit
We gave the oath of allegiance to Allah's Apostle that we would listen to and obey him both at the time when we were active and at the time when we were tired and that we would not fight against the ruler or disobey him, and would stand firm for the truth or say the truth wherever we might be, and in the Way of Allah we would not be afraid of the blame of the blamers. (See Hadith No. 178 and 320)