“Ibn Habban” says in “Al-Thuqat” book:
I’ve visited the grave of Imam “Reza” [AS] several times. When I was in “Tūs”, any problem that I would face, I’d visit the grave of “‘Alī ibn Mūsā al-Rezā”- peace be upon him and his ancestor – and pray until my problem is solved, my prayer would get fulfilled and my problem would get solved. I’ve experienced this act several times and got response. May god get our life while loving Muhammad [PBUH] and his “Ahl al-Bayt”- peace be upon him and his “Ahl al-Bayt”.
“Ibn Habban” – Al-Thuqat – vol. 8, p 457