Addressing Imam Ali (Peace Be Upon Him), Prophet Muhammad (Blessings of God Upon Him and His Progeny) said: "O Ali, he who goes on pilgrimage to me or one of my descendents, will be visited by me on the Day of Judgment and will be saved by me from the fear of the Day of Judgment." (Thavab ul A'maal, p. 242, Kamil ul Ziyaraat, p. 41, Bihar ul Anwar, vol. 100, p. 123)
There are four traditions from three Imams on the reward for pilgrimage to Ma'soomah's shrine. (Tuhfat ul Muzafariya)
1 - Imam Sadiq (A.S) says: "Indeed, there is a House of God and that is Mecca, there is a shrine for the Holy Prophet (PBUH) and that is in Medina, and there is a shrine for the Commander of the Faithful and that is in Kufa, and there is a shrine for we the Household of the Prophet Mohammad (PBUH) and that is in Qom. Soon, a lady, named Fatima, will be laid to rest in that city; one who goes on pilgrimage to her, will be rewarded in heaven."
2 - In an answer to a question raised by Sa'd bin Sa'd about Fatima the daughter of Musa bin Ja'far, Imam Reza (Ali bin Musa Reza), said: He who goes on pilgrimage to her, will be rewarded in the heaven."
3 - Addressing Sa'd, Imam Reza said: Is there any grave of our people in your place? He said, yes, that of Fatima, daughter of Musa bin Ja'far. The Imam said: Heaven will be the reward of he who goes on pilgrimage to her with knowledge and awareness."
4 - Imam Mohammad Taqi (A.S) has said: Paradise will be the reward of he who goes on pilgrimage to my aunt in Qom.
source : www.tebyan.net