The Effect of Hearts on Learning the Religion

Imām Ibn Taimiyyah, may Allāh have mercy on him, said:

A heart, when it’s sensitive, pliant, and soft, takes in knowledge [of Islam] easily, without difficulty—and the knowledge becomes firmly implanted within it, stays put, and has an impact. [But] if [a heart] is hard, harsh, and rough, taking in [Islamic] knowledge becomes difficult and tough.

Majmūʿ Al-Fatāwá, vol. 9, p. 315.