Sahih Muslim Book 4, Hadith Number 1276.

Chapter : He who came up with the Rak’ah, he in fact came up with the prayer (led in congregation with the Imam).

‘Abdullah b. ‘Amr b. al-‘As reported: The Messenger of Allah (may peace be upon him) was asked about the times of prayers. He said: The time for the morning prayer (lasts) as long as the first visible part of the rising sun does not appear and the time of the noon prayer is when the sun declines from the zenith and there is not a time for the afternoon prayer and the time for the afternoon prayer is so long as the sun does not become pale and its first visible part does not set, and the time for the evening prayer is that when the sun disappears and (it lasts) till the twilight is no more and the time for the night prayer is up to the midnight.