Musannaf Ibn Abi Shayba 27:874

Waki' narrated to us, he said: Isma'il bin Abi Khalid narrated to us, from Qays, he said: The Messenger of Allah (may Allah bless him and grant him peace) said to Bilal: "What have you done regarding the riders of the Bajiliyyin? Begin with the Ahmasiyyin before the Qasiriyyin."