Abu Dawud Book 2, Hadith Number 1271.

Chapter : The view that the praying of the two rakahs after the afternoon prayer is permissible when the sun is at its height.

Narated By 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 (PBUH) 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.