It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) allotted two shares for the horse and one share for the rider (on the occasion of the Battle of Khaybar).
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5412
Hadith Gradingحکم دارالسلام:إسناده صحيح ، خ : 2863، م :1762.