What did Ibn 'Abbas (peace be upon him) narrate to Ash-Shu`bi about the Prophet Muhammad (saw) leading a prayer at a grave separate from the others?
 Narrated Ash-Shaibani:                     Ash-Shu`bi said, "Somebody who passed along with your Prophet (p.b.u.h) by a grave that was separate from the other graves informed me (saying), "The Prophet led us (in the prayer) and we aligned behind him." We said, "O Abu `Amr! Who told you this narration?" He replied, "Ibn `Abbas."