Hadith 503180
Chapter 8: Prayer in Congregation - كتاب صلاة الجماعة
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَلِيَّ بْنَ أَبِي طَالِبٍ، وَعَبْدَ اللَّهِ بْنَ عَبَّاسٍ، كَانَا يَقُولاَنِ الصَّلاَةُ الْوُسْطَى صَلاَةُ الصُّبْحِ . قَالَ مَالِكٌ وَقَوْلُ عَلِيٍّ وَابْنِ عَبَّاسٍ أَحَبُّ مَا سَمِعْتُ إِلَىَّ فِي ذَلِكَ .
Yahya related to me from Malik that he had heard that AIi ibn Abi Talib and Abdullah ibn Abbas used to say, "The middle prayer is the prayer of subh." Malik said, "Out of all that I have heard about the matter, I prefer what Ali ibn Abi Talib and Abdullah ibn Abbas said."
Reference Muwatta Malik 503180
USC-MSA web (English) reference : Book 8, Hadith 29