Sunan at-Tirmidhi (Jami-al-Tirmidhi), Chapter: Salah (Prayers)

Ala ibn Abdur Rahman (RA) visited Sayyidina Anas (RA) at his home after offering the Salah of Zuhr. His home was next to the mosque. Sayyidina Anas (RA) said, "Let us stand up and offer the Asr Salah."They stood up and offered Salah of Asr. When they had finished, Sayyidina Anas (RA) said, "I had heard Allah's Messenger (SAW) say that it is a hypocrite's Salah that he sits by watching the sun till it is between the two horns of the devil, he rises and pecks four times, remembering Allah but a little." [Ahmed 12511, Muslim 622, Abu Dawud 413, Nisai 507]