And it is narrated in some books of Ziyaraat that surely Imam Reza (a.s.) said to Sa’ad al-Asha’ri: O Sa’ad, one of our graves is in your vicinity.

Sa’ad: May I be sacrificed for you. Do you mean the grave of Fatima Bint Moosa Bin Jafar (a.s.)?

He (a.s.) replied: Yes. One who visits her recognizing her right then Paradise is obligatory upon him.
Zaad al-Maad p 547