Musannaf Ibn Abi Shayba 3:296

I prayed beside Hafs ibn 'Asim. When I prostrated, I spread my fingers apart and tilted my palms away from the Qibla. When I finished the prayer, he said, "O son of my brother, when you prostrate, bring your fingers together and direct your hands toward the Qibla, for the hands prostrate along with the face."