Sahih al-Bukhari 615
Narrated Abu Huraira:
Allah's Messenger (ﷺ) said, "If the people knew the reward for pronouncing the Adhan and for standing in 
the first row (in congregational prayers) and found no other way to get that except by drawing lots 
they would draw lots, and if they knew the reward of the Zuhr prayer (in the early moments of its 
stated time) they would race for it (go early) and if they knew the reward of `Isha' and Fajr (morning) 
prayers in congregation, they would come to offer them even if they had to crawl."
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، قَالَ أَخْبَرَنَا مَالِكٌ، عَنْ سُمَىٍّ، مَوْلَى أَبِي بَكْرٍ عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏
"‏ لَوْ يَعْلَمُ النَّاسُ مَا فِي النِّدَاءِ وَالصَّفِّ الأَوَّلِ، ثُمَّ لَمْ يَجِدُوا إِلاَّ أَنْ يَسْتَهِمُوا عَلَيْهِ لاَسْتَهَمُوا، وَلَوْ يَعْلَمُونَ مَا فِي التَّهْجِيرِ لاَسْتَبَقُوا إِلَيْهِ، وَلَوْ يَعْلَمُونَ مَا فِي الْعَتَمَةِ وَالصُّبْحِ لأَتَوْهُمَا وَلَوْ حَبْوًا ‏"‏‏.‏