The Messenger of Allah ﷺ said, "When one of you rises at night and the Quran becomes confused on his tongue so that he does not know what he is saying, let him lie down."
قال رسول الله ﷺ: إذا قام أحدكم من الليل فاستعجم القرآن على لسانه فلم يدر ما يقول: فليضطجع.
Muslim narrated it in the chapter on the Prayer of Travelers (787), from Muhammad bin Rafi, who said, Abdul-Razzaq narrated to us, who said, Mamar narrated to us, from Hammam bin Munabbih, who said, "This is what Abu Hurairah narrated to us, from Muhammad, the Messenger of Allah ﷺ," and he then went on to mention several hadiths, including this one. It is also found in Musannaf Abdul-Razzaq (500), where he added, before "let him lie down," the words "let him leave."This hadith is one of those that Muslim narrated alone, without Bukhari. As for what Baghawi said in Sharh al-Sunnah (4/58), "This is a hadith agreed upon as to its soundness, narrated by Muslim from Muhammad bin Rafi, from Abdul-Razzaq..." this contains a mistake, because Bukhari did not narrate this hadith, neither through the route of Hammam bin Munabbih nor through any other route. It is Baghawi's habit that when he says "agreed upon," he means by it Bukhari and Muslim, though he does not commit himself to specifying the route through which each of them narrated it. Sometimes he mentions the route of both of them, and sometimes he is content to mention the route of only one of them, but the basis of the hadith is found in both of their collections, so take note.As for his saying "fastajam," it means, "became unclear and obscure."