Muwatta Malik, Book 9, Hadith 16 (USC-MSA) ⓘ
Yahya related to me from Malik from Nafi that he used to travel one mail-stage with Ibn Umar, and he would not shorten the prayer.
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّهُ كَانَ يُسَافِرُ مَعَ ابْنِ عُمَرَ الْبَرِيدَ فَلاَ يَقْصُرُ الصَّلاَةَ .
also referenced under: Book 9, Hadith 344 (In-Book)