The Prophet ﷺ said, "The eyes of the prophets sleep, but their hearts do not sleep."
قال النبي ﷺ: إن الأنبياء تنام أعينهم، ولا تنام قلوبهم.
Bukhari narrated it in the Book of Tawhid (7517), and Muslim in the Book of Faith (162), both from the hadith of Sulayman bin Bilal, from Sharik bin Abdullah, who said, I heard Anas bin Malik, and he mentioned the hadith at length in the story of the Night Journey and Ascension, and it will come in full later.