Sahih al-Bukhari 720, 721
Narrated Abu Huraira:
The Prophet (ﷺ) said, "Martyrs are those who die because of drowning, plague, an Abdominal disease, or 
of being buried alive by a falling building." And then he added, "If the people knew the Reward for 
the Zuhr prayer in its early time, they would race for it. If they knew the reward for the `Isha' and the 
Fajr prayers in congregation, they would join them even if they had to crawl. If they knew the reward 
for the first row, they would draw lots for it."
حَدَّثَنَا أَبُو عَاصِمٍ، عَنْ مَالِكٍ، عَنْ سُمَىٍّ، عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ الشُّهَدَاءُ الْغَرِقُ وَالْمَطْعُونُ وَالْمَبْطُونُ وَالْهَدْمُ ‏"‏‏.‏ وَقَالَ ‏"‏ وَلَوْ يَعْلَمُونَ مَا فِي التَّهْجِيرِ لاَسْتَبَقُوا ‏{‏إِلَيْهِ‏}‏ وَلَوْ يَعْلَمُونَ مَا فِي الْعَتَمَةِ وَالصُّبْحِ لأَتَوْهُمَا وَلَوْ حَبْوًا، وَلَوْ يَعْلَمُونَ مَا فِي الصَّفِّ الْمُقَدَّمِ لاَسْتَهَمُوا ‏"‏‏.‏