‘Abdullah b. Mas’ûd – Allâh be pleased with him – said:
Falling asleep when remembering Allâh is from Shaytân; if you want you can test this: when you lie down and want to fall asleep, try remembering Allâh ‘azza wa jall.
Al-Bukhârî, Al-Adab Al-Mufrad. Graded sahîh by Shaykh Al-Albânî in Sahîh Al-Adab Al-Mufrad Vol. 1 p490.