Although there are similarities between all members of Ahlul Bayt and they are from the same light, there is a special link between Imam Husayn and Imam Mahdi. In this paper, verses from the Qur’an and hadiths of the Ahlul Bayt will be used to demonstrate this connection. Indeed, Imam Mahdi is from the progeny of Imam Husayn who will rise on the Day of Ashura and will speak of his grandfather’s oppression. Imam Husayn also spoke of Imam Mahdi avenging for him, and helping Imam Husayn is similar to helping Imam Mahdi. Moreover, one of the best deeds on the birth of Imam Mahdi is to recite Ziyarah of Imam Husayn, as renewing one’s allegiance with Imam Husayn is renewing it with Imam Mahdi.