Arabic hadith text
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّهُ كَانَ يُسَافِرُ إِلَى خَيْبَرَ فَيَقْصُرُ الصَّلاَةَ ‏.‏
Translation

Yahya related to me from Malik from Nafi from Ibn Umar that heused to travel to Khaybar and he would shorten the prayer.