Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 1358
Abu Dharr reported: (The Messenger of Allah) said: How would you, or how would thou, act if you survive to live among people who defer prayer beyond the (prescribed) time? (The narrator said: Allah and His Messenger know best). whereupon he said: Observe prayer at its prescribed time, but if the Iqama is pronounced for (congregational) prayer, then observe prayer along with them. for herein is an excess of virtue.