7-24 (The compiler of the book narrated) that his father - may God be pleased with him - narrated that Ali ibn Ibrahim ibn Hashim quoted his father, on the authority of Himad, on the authority of Zurarah that Abi Ja’far al-Baqir (MGB) said, “You perform the prostration on seven bones: the forehead; the palms of the hands; the ends of the knees; the big toes of the feet; and the tip of the nose. The first seven is a must but touching the tip of the nose to the ground during prostration is just recommendable.”