Abu Dawud
Prayer
Book Number: 002 / Hadith Number: 429
Narated By AbuQatadah ibn Rab'i : Allah , the Exalted said: I made five times' prayers obligatory on your people, and I took a guarantee that if anyone observes them regularly at their times, I shall admit him to Paradise; if anyone does not offer them regularly, there is no such guarantee of Mine for him.