Sahih Bukhari Volume 1, Book 10, Hadith 721

قَالَ ‏"‏ وَلَوْ يَعْلَمُونَ مَا فِي التَّهْجِيرِ لاَسْتَبَقُوا ‏{‏إِلَيْهِ‏}‏ وَلَوْ يَعْلَمُونَ مَا فِي الْعَتَمَةِ وَالصُّبْحِ لأَتَوْهُمَا وَلَوْ حَبْوًا، وَلَوْ يَعْلَمُونَ مَا فِي الصَّفِّ الْمُقَدَّمِ لاَسْتَهَمُوا ‏"‏‏

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."