Al-Imām ibn al-Qayyim [may Allāh have mercy on him] said:
“From among the most harmful things to the servant are idleness and free time, for the essence of a person is never to be idle. Certainly, if you do not occupy yourself with that which benefits it, then you will inevitably occupy it with that which harms it.”
Dār ul-Hijratayn | Page 281 | Al-Imām ibn al-Qayyim [may Allāh have mercy on him]