Musannaf Ibn Abi Shayba 21:303

Ghundar narrated to us, from Shu'bah, from Mansur, from Talq ibn Habib, from Abdullah ibn Amr, who said: "For me to say them—meaning: 'Subhan Allah, wal-hamdu lillah, wa la ilaha illallah, wallahu akbar' (Glory be to Allah, and praise be to Allah, and there is no god but Allah, and Allah is the Greatest)—is more beloved to me than to provide their number in horses with their reins."