Prayer (Kitab Al-Salat): Detailed Rules of Law about the Prayer during Journey
Dawud :: Book 4 : Hadith 1271
Narrated Abdullah ibn Abbas:
Some reliable people testified before me, and among them was Umar ibn al-Khattab, and most reliable in my eyes was Umar: The Prophet of Allah (peace_be_upon_him) said: There is no prayer after the dawn prayer until the sun rises; and there is no prayer after the afternoon prayer until the sun sets.