صحیح مسلم · Hadith 704

Ibn 'Umar said: 'Umar asked the verdict of the Shari'ah from the Apostle ( ‌صلی ‌اللہ ‌علیہ ‌وسلم ‌ ) thus: Is it permissible for any one of us to sleep in a state of impurity? He (the Prophet said: Yes, he must perform ablution and then sleep and take a bath when he desires.