and his prayer is deficient, but he is not required to repeat it. As for deliberate additions to the prayer, they all agree that some additions invalidate it when made deliberately but not when made inadvertently. When made deliberately, however, they invalidate the prayer, so there are no prostrations to perform; when made inadvertently, they say that the addition is excused, so the prostrations are not obligatory.

Some have cited as evidence the reported wording of the Prophet, peace and blessings be upon him, in the hadith concerning doubt:

“The rak‘ah and the two prostrations would count as voluntary worship.”

This wording is not found in the Sahīh. The wording in the Sahīh is:

“Let him disregard his doubt and proceed on the basis of what he is certain of, then perform two prostrations before saying the salām. If he has prayed five rak‘ahs, they will make his prayer even-numbered; and if he has prayed a full four, they will humiliate Satan.”

He thus commanded the prostrations and explained their wisdom, whether the person had prayed five rak‘ahs or four. He said:

“If he has prayed five rak‘ahs, they will make his prayer even-numbered.”

This implies that offering voluntary prayer with an odd number of rak‘ahs is not permissible. Rather, Allah has commanded that the daytime prayers be made odd-numbered through Maghrib, and the night prayers through Witr. Here, when a person in doubt has unknowingly prayed five rak‘ahs, he made the two prostrations take the place of one rak‘ah, thereby making his prayer even-numbered.

He said:

“And if he has prayed a full four, adding nothing to the prayer, they will humiliate Satan.”

Thus, this wording—“The rak‘ah and the two prostrations would count as voluntary worship for him”—cannot be used as evidence unless it is established that it was spoken by the Prophet, peace and blessings be upon him.