وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، أَنَّهُ قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏"‏ إِذَا بَدَا حَاجِبُ الشَّمْسِ فَأَخِّرُوا الصَّلاَةَ حَتَّى تَبْرُزَ وَإِذَا غَابَ حَاجِبُ الشَّمْسِ فَأَخِّرُوا الصَّلاَةَ حَتَّى تَغِيبَ ‏"‏ ‏.‏

Yahya related to me from Malik from Hisham ibn Urwa that hisfather said that the Messenger of Allah, may Allah bless him and granthim peace, used to say, "Delay the prayer when the edge of the sunappears until it is completely in view, and delay the prayer when theedge of the sun is disappearing until it has completely disappeared." Translation Not Available

Book Ref: Muwatta Imam Malik Book 15 Hadith 517
Web Ref:  Muwatta Imam Malik Book 15 Hadith 45