Muwatta Malik, Book 9, Hadith 343 (In-Book) ⓘ
Yahya related to me from Malik from Ibn Shihab from Salim ibn Abdullah that Abdullah ibn Umar used to shorten the prayer when he travelled for a whole day.
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَالِمِ بْنِ عَبْدِ اللَّهِ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَقْصُرُ الصَّلاَةَ فِي مَسِيرِهِ الْيَوْمَ التَّامَّ .
also referenced under: Book 9, Hadith 15 (USC-MSA)