Sa’ad from Ahmad ibn Muhammad ibn Isa from al-Husayn ibn Sa'id from Fadalah ibn Ayyub from Mu'awiyah ibn Wahb, who said: I said to Abu Abdillah عليه السلام, peace be upon him: “What is the minimum distance at which the traveller shortens the prayer?” Imam عليه السلام said: “A ‘barid’ going, and a ‘barid’ returning.”