Sahih Bukhari Volume 1, Book 11, Hadith Number 589

Narated By Abu Huraira : Allah’s Apostle 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.”