The Messenger of Allah ﷺ said, "When one of you rises at night and the Quran becomes difficult on his tongue so that he does not know what he is saying, let him lie down."
حدثنا أحمد بن حنبل حدثنا عبد الرزاق أخبرنا معمر عن همام بن منبه
قال رسول الله ﷺ إذا قام أحدكم من الليل فاستعجم القرآن على لسانه فلم يدر ما يقول فليضطجع
Sourcing, Muslim narrated it in "Prayer of the Traveler," chapter on the command regarding one who becomes drowsy during his prayer, etc., hadith no. 787, from the hadith of Abdul-Razzaq, with this wording. It is also found in his Musannaf, hadith no. 4221, in Musnad Ahmad, 2/318, and in Sahifah Hammam bin Munabbih, hadith no. 116.