The Prophet’s words in the hadith of Abū Sa‘īd,

“If any of you is in doubt,”

address someone whose doubt persists because he cannot exercise his judgment, having no indication or evidence that makes either possibility more likely, or because he has exercised his judgment and reflected but still finds neither possibility more likely.

Anyone who says that there is no evidence here to distinguish between the two possibilities is mistaken. If he is leading the prayer, he may find evidence in the agreement of those praying behind him. He may also rely on information given by someone else, even if that person is not praying with him, and thereby come to regard one possibility as more likely.

He may remember what he recited during the prayer, recalling that he recited two surahs in two units, and thus know that he has prayed two units, not one. He may remember having recited the first tashahhud (testimony of faith), and thus know that he has prayed two units, not one, and three, not two. He may remember having recited al-Fātihah alone in one unit and then in another, and thus know that he has prayed four, not three. He may remember having prayed two units after the first tashahhud, and thus know that he has prayed four, not three, and two, not one. He may remember having recited the first tashahhud and that his doubt concerns a unit after it, and thus know that he has prayed three, not two.

Another possibility is that something occurs during one of the units—whether supplication and humble devotion, coughing or the like, or something else—by which he recognizes that particular unit and knows that he prayed one, two or three units before it. His doubt is thereby dispelled.

Such cases are too varied to be exhaustively listed. People are constantly uncertain whether things happened or not. Then they remember and find indications that those things did happen, thereby dispelling