Abu al-Muthanna al-Mustazill said: I heard Sayyiduna Jarir bin Abdullah (may Allah be pleased with him), who was our governor, saying: I pledged allegiance to the Messenger of Allah (peace and blessings be upon him), then I went back, and he (peace and blessings be upon him) called me and said: "I will not accept your pledge until you pledge again, and on the condition of sincere goodwill towards every Muslim." So I pledged allegiance to him (peace and blessings be upon him) again.
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 2444