Musnad Ahmad 575:2

'Affan narrated to us, Shu'bah narrated to us, Sa'd ibn Ibrahim said: He informed me, he said: I heard Nasr ibn 'Abd al-Rahman, from his grandfather Mu'adh, that he performed Tawaf with Mu'adh ibn 'Afra', and he did not pray after the 'Asr or after the Subh. So he said: "What prevents you from praying?" He said: "I heard the Messenger of Allah, peace and blessings of Allah be upon him, forbidding, or saying: 'There is no prayer after the Subh until the sun rises, and after the 'Asr until the sun sets.'"