In Islamic thought, “unity“ has a high status in continuation of the holy Prophet (S) and Imams’ (A) mission. Thus, a thorough research of the conduct and speech of Imam Ali (A), who was the herald of unity, would show the status of unity and its various dimensions in true Islam. Imam Ali (A) viewed unity as the fruit of the mission of the holy Prophet (S), among whose results is burying mutual rancor and developing brotherhood and affection among Muslims. Criticizing disunited nations, Imam Ali (A) mentions that division leads to destruction of dignity and honour while unity leads to the descent of divine blessings.