1. Ali ibn Ibrahim has narrated from his father from Ibn Abi ‘Umayr from Hammad from al-Halabiy who has said the following: “Abu ’Abd Allah (a.s.), was asked about a man who becomes confused and does not know if he has done one or two Sajdah (prostrations). He (the Imam) said, ’He performs another Sajdah (prostration) and after completion of Salah (prayer) two Sajdah (prostration) because of mistake is not necessary.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

2. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from al-Husayn ibn Sa‘id from Muhammad ibn Sinan from ibn Muskan from abu Basir from who has said the following: “I once asked abu ’Abd Allah (a.s.), about a man who doubts and does not know if he has performed one or two Sajdah (prostrations). He (the Imam) said, ‘He performs Sajdah (prostration) to ascertain that it is two Sajdah (prostrations).”’

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

3. It is a narration from him (narrator of previous Hadith) by Ahmad ibn Muhammad from Ahmad ibn Muhammad ibn abu Nasr and Ali ibn Muhammad from Sahl ibn Ziyad from Ahmad ibn Muhammad ibn abu Nasr who has said the following: “I once asked abu al-Hassan (a.s.), about a man who performs one Rak’at of Salah (prayer), then he remembers in the second Rak’at in Ruku’ (bowing down on one’s knees) position that he has omitted one Sajdah (prostration) of the first Rak’at. He said, ‘Abu al-Hassan (a.s.), would say that if you omit Sajdah (prostration) in the first Rak’at and do not know if it is one or two; perform Salah (prayer) again until it is correct to say that two Sajdah (prostrations) are performed.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

4. Ali ibn Ibrahim has narrated from his father from Ibn Abi ‘Umayr from ‘Amr ibn ‘Uthman al-Khazzaz from al-Mufaddal ibn Salih from Zayd al-Shahham who has said the following: “About a man who doubts and does not know if he has performed one or two Sajdah (prostrations), abu ‘Abd Allah (a.s.), has said, ‘He performs one more Sajdah (prostration).”’

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.