During [every] day and night, Ibn ‘Ataa would [only] sleep for two hours.
Abu Bakr al-Anbaaree said that al-Imaam, al-Haafith Abu ‘Ubayd would divide the night into thirds; so he would pray a third of it, and sleep a third of it, and author books [during] a third of it.
It is not possible to attain knowledge while at ease and rest.
Indeed the heart which loves Allaah ‘Azza wa Jall, loves to become tired and exhausted for [the Sake of] Allaah; one will certainly never attain the love of Allaah whilst at rest and ease.
Resting is in being at the service of the Muslims.