Imām al-Ash`arī says: During the first ten days of one Ramadān, I saw RasūlAllāh (sall allāhu `alayhi wa sallam). He said: "O `Alī, aid the madhāhib that are ver itably reported by me, because only that is the Truth." I woke up and was perplexed about this grave matter.

How Imām al-Ash`arī left the Mu`tazilah to join Ahl al-Sunnah
Imām Ibn `Asākir