Ali ibn Ibrahim from Abdullah ibn al-Mughirah from Abdullah ibn Sinan, who said: I asked Abu Abdillah عليه السلام, peace be upon him, about a man whose garment was soiled by janabah (semen) or blood. Imam عليه السلام said: "If he knew that janabah or blood had touched his garment before he prayed, and then he prayed in it without washing it, he must repeat whatever prayers he performed. But if he suspected that something had touched him and he inspected it and did not see anything, it suffices for him to sprinkle it with water."