Muwatta Malik, Book 54, Hadith 35 (USC-MSA) ⓘ
Malik related to me from Abd ar-Rahman ibn Harmala from Amr ibn Shuayb from his father from his father that the Messenger of Allah, may Allah bless him and grant him peace, said, "One rider is a shaytan. Two riders are two shaytans, and three are a riding-party."
حَدَّثَنِي مَالِكٌ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ حَرْمَلَةَ، عَنْ عَمْرِو بْنِ شُعَيْبٍ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " الرَّاكِبُ شَيْطَانٌ وَالرَّاكِبَانِ شَيْطَانَانِ وَالثَّلاَثَةُ رَكْبٌ " .
also referenced under: Book 54, Hadith 1801 (In-Book)