Sayyiduna Ubadah bin al-Samit (may Allah be pleased with him) said: We pledged allegiance to the Messenger of Allah (peace and blessings be upon him) to hear and obey, "in hardship and ease, in what we like and dislike, that we would not contest the authority of those entitled to it, that we would stand by (or speak) the truth wherever we are, and that we would not fear the blame of any blamer."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قتال أهل البغي / 16551