The Dislike of Sleeping After the Fajr Prayer
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 78
وَقَالَ رَسُولُ اَللَّهِ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ: «مَنْ جَلَسَ فِي مُصَلاَّهُ مِنْ صَلاَةِ اَلْفَجْرِ إِلَى طُلُوعِ اَلشَّمْسِ سَتَرَهُ اَللَّهُ مِنَ اَلنَّارِ.
The Messenger of Allah صلى الله عليه وعلى آله وسلم said: "Whoever remains seated in their place of prayer after the Fajr prayer until the sun rises, Allah سبحانه وتعالى will protect them from the Fire."
- Ṣaḥīḥ al-Faqīh