MISTAKES FOR WHICH SAJDAH SAHV IS WAJIB

If any of the following five types of mistakes occurs forgetfully during a wajib salat, then it is wajib to perform Sajdah Sahv immediately after completing the salat.

(1) Talking forgetfully during salat (or even uttering a single word which has a meaning, e.g. saying ‘Ah’ in pain).

(2) Reciting Salam forgetfully at a wrong place during salat. (For example, if you recite Salam after Tashahhud in 2nd rakat in a 4-rakat salat). Salam in a salat has three parts. Sajdah Sahv becomes wajib if 2nd or 3rd part of Salam is recited forgetfully. If only 1st part is recited forgetfully, then Sajdah Sahv is not wajib, but it is mustahab to perform.

(3) Forgetting to recite Tashahhud during salat. If you forget Tashahhud after 2nd rakat, but remember it before the ruku of next rakat, then you should return and perform it. And after the salat, perform Sajdah Sahv for performing additional standing (qiyam).

(4) Adding or omitting something forgetfully during salat, but that addition or omission does not make salat void. (Examples:
(i) reciting Tashahhud after 1st rakat or after 3rd rakat in a 4-rakat salat;
(ii) doing an extra sajda by mistake;
(iii) forgetting zikr in a sajdah or ruku,
(iv) forgetting second surah in 1st rakat or 2nd rakat, etc).

(5) When doubts occurs in the number of rakats in a 4-rakat salat, if it is 4th or 5th rakat, or it is 4th or 6th rakat, or it is 4th or more rakat (as explained in Fiqh Notes #2).

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