Arabic hadith text
وَحَدَّثَنِي مَالِكٌ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، قَالَ وَهُوَ مُسْنِدٌ ظَهْرَهُ إِلَى الْكَعْبَةِ مَنْ أَخَذَ ضَالَّةً فَهُوَ ضَالٌّ ‏.‏
Translation

Malik related to me from Yahya ibn Said from Said ibn al-Musayyabthat Umar ibn al-Khattab said while he was leaning his back againstthe Kaba, "Whoever takes a stray is astray."