Musannaf Ibn Abi Shayba 3:302

Hushaym narrated to us, from Husayn, from ‘Amr ibn Murrah, from Talq ibn Habib, regarding the saying of Allah (the Exalted): "And all faces shall be humbled before the Ever-Living, the Sustainer of existence." He said: "It is the prostration upon the forehead, the two palms, the two knees, and the two feet."