Narrated `Abdullah bin Abi Qatada: My father said, "The Prophet used to prolong the first rak`a of the Zuhr prayer and shorten the second one and used to do the same in the Fajr prayer."
Hadith ReferenceSahih Bukhari / The Book of Adhan (Sufa-tus-Salat) / Hadith: 779
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة