من لا يحضره الفقيه, volume 1, page 405

Hadith.1200 - Ubayd ibn Zurarah reported from Imam Jafar ibn Muhammad Al-Sadiq (as) regarding a man who joined the prayer with the Imam but had missed one rak'ah. After the Imam concluded the prayer, he left with the people and then remembered that he had missed a rak'ah. Imam (as) said: "He should perform one rak'ah”.

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.

Hadith.1201 - In the book of Ziyad ibn Marwan al-Qandi and in the Nawadir of Muhammad ibn Abi Umayr, it is narrated that Imam Jafar ibn Muhammad Al-Sadiq (as) said regarding a man who led a group in prayer from the time they left Khurasan until they reached Mecca, and then it was discovered that he was a Jew or a Christian: "They do not need to repeat their prayers”.

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.

Hadith.1202 - Ali ibn Ja'far was asked about his brother Imam Musa ibn Jafar Al-Kadhim (as) about a woman leading other women in prayer: "What is the limit of raising her voice in the takbir (saying 'Allahu Akbar') and in recitation?" Imam (as) replied: "To the extent that they can hear her."

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.

Hadith.1203 - Ammar al-Sabati narrated from Imam Jafar ibn Muhammad Al-Sadiq (as) who said: "I asked him about a man who, while praying behind an Imam, forgets to say the tasbih (glorification) during Sujood (prostration) or ruku' (bowing) or forgets to say something between the two prostrations." Imam (as) said: "There is no obligation upon him (no penalty)."

Translation: Bab Ul Qaim Publications — attributed by Thaqalayn·The Arabic above is the original.