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 ‏"‏ ‏.‏

Malik related to me from Abd ar-Rahman ibn Harmala from Amr ibnShuayb from his father from his father that the Messenger of Allah,may Allah bless him and grant him peace, said, "One rider is ashaytan. Two riders are two shaytans, and three are a riding-party." Translation Not Available

Book Ref: Muwatta Imam Malik Book 54 Hadith 1801
Web Ref:  Muwatta Imam Malik Book 54 Hadith 35