Badāʾ is one of the certain teachings of Shia and there is a disagreement among Islamic philosophers and theologians about its real meaning. Among Islamic philosophers, Mulla Sadra has a unique solution for this question. He believes that Badāʾ occurs in the level of the seven heavens as mentioned in the holy Quran, while he considers this level in accordance with the world of imagination. Ommalah angles are responsible to manage the affairs of the world of matter, and therefore Badāʾ happens for them and as they are the messengers of Allah, Badāʾ is also attributed to Allah. This paper explains the theory of Mulla Sadra about Badāʾ and the answers he has given to the doubts on this issue by considering the verses of the holy Quran and the Islamic traditions.