حَدَّثَنَا ابْنُ الْمُثَنَّى، حَدَّثَنَا عَبْدُ الأَعْلَى، عَنْ سَعِيدٍ، عَنْ قَتَادَةَ، قَالَ الْجَلَبُ وَالْجَنَبُ فِي الرِّهَانِ ‏.‏

Qatadah said “Taking another horse behind one’s horse to urge it on and taking another horse at one’s side are (done) in a horse race. Translation Not Available

Book Ref: Sunan Abi Dawud Book 15 Hadith 2582
Web Ref:  Sunan Abi Dawud Book 14 Hadith 2576