Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 924
Simak asked Jabir b. Samura about the prayer of the Apostle (may peace be upon him). He said: He (the Holy Prophet) shortened the prayer and he did not pray like these people then, and he informed me that the Messenger of Allah (may peace be upon him) used to recite" Qaf. By the (Glorious) Qur'an," and a passage of similar length.