Iqmal ud Din:
Narrated from Muhammad Ibn Sinan, Amir Ibn Shamir, Jabir and Abu Jaffir:

"THE KNOWLEDGE OF ALMIGHTY ALLAH'S BOOK AND THE SUNNAH OF HIS MESSENGER WILL GROW AND FLOURISH LIKE A PLANT IN OUR MAHDI'S HEART."

(Kitab al-Ghaybat, [Bihar al-Anwar, Vol. 51], Ansariyan Publications, collected by: Muhammad Baqr al-Majlis, Iran-Qum, 2003, p. 72)