Musnad Ahmad 30:108

Narrated to us Abd al-Rahman, from Malik, from Sumayy, from Abu Salih, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "If the people knew what is in the call (to prayer) and the first row, and then they could not find [a way to attain it] except by drawing lots for it, they would draw lots for it. And if they knew what is in coming early (to the prayer), they would race toward it. And if they knew what is in the Isha and the Fajr (prayers), they would come to them even if they had to crawl."