It is narrated from Sayyiduna Shaybah bin Uthman (may Allah be pleased with him) that he said: The Messenger of Allah (peace and blessings be upon him) led us in prayer in the Mosque of al-Khayf, then said: "There are three things about which the heart of a believer never harbours deceit: sincerity in deeds, sincere counsel to the leaders of the Muslims, and holding firmly to their community, for their supplication encompasses them from all sides."
Hadith Referenceالمعجم الكبير للطبراني / باب الشين / 7163