The Messenger of Allah ﷺ said, "When one of you rises at night to pray and the Quran becomes tangled on his tongue so that he no longer knows what he is saying, let him lie down and sleep."
وقال رسول الله ﷺ إذا قام أحدكم من الليل فاستعجم القرآن على لسانه فلم يدر ما يقول فليضطجع
A sahih hadith, narrated by Ibn Majah in the Prayer chapter from Yaqub bin Humayd. It was also narrated by Muslim in the Prayer chapter from Muhammad bin Rafi, and by Abu Dawud in the Prayer chapter from Ahmad bin Hanbal.