Salim bin 'Abdullah bin 'Umar bin Al-Khattab (May Allah be pleased with them) reported, on the authority of his father, that the Messenger of Allah (ﷺ) said, "What an excellent man 'Abdullah is! If only he could perform optional prayers at night." Salim said that after this, (his father) 'Abdullah slept very little at night.[Al-Bukhari and Muslim].