Chapter on the Prayer Times (Mawaqit)

From him, from Muhammad ibn Abi Hamzah and Husayn ibn Hashim and Ali ibn Ribat and Safwan ibn Yahya from Ya‘qub ibn Shu‘ayb from Abu Abdillah عليه السلام, who said: I asked Him عليه السلام about the Dhuhr prayer. Imam عليه السلام said: "When the shadow is one arm’s span (dhira‘)." I asked: "An arm’s span from what?" Imam عليه السلام said: "An arm’s span from your own shadow." I asked: "And the ‘Asr prayer?" Imam عليه السلام said: "Half of that." I asked: "That is one hand-span (shibr)." Imam عليه السلام said: "A hand-span, and is a hand-span not considerable?"