Rule of Congregational Prayers
Congregational Prayers is one of the most important recommended acts, and it is one of the greatest Islamic rites. Great emphasis has been laid on it in the narrations. It is recommended that obligatory prayers, especially the daily prayers, are performed in congregation, and more emphasis has been laid on congregational prayers for Fajr, Maghrib and Isha, and also for those who live in the neighborhood of a mosque, and are able to hear its Adhan.
Most of the Shiite religious authorities (jurists) have permitted following a Sunni prayer leader in their congregational prayers. Verdicts of some of the renowned jurists are as under:
The Grand Jurists:
Imam Khomeini (may his soul rest in peace): “Shiites can follow a Sunni prayer leader.”
Khamenei: “There is no problem in attending their Friday and congregational prayers for the sake of unity.”
Khoei (ra) and Tabrizi (ra): “It is permissible to go to Sunni mosques and offer congregational prayers with Sunnis provided that one himself should engage in reciting Hamd and Surah.”
Tabrizi (ra): “If a person stands at a place in a Sunni mosque where part of the floor is covered with stone (slates), it is mandatory to do Sajda on the same stone.”
 - Imam Khomeini, Tauzihul Masail (with connotation), vol.1, pg.767-768, Issue No.1399.
 - Istifta’at of Imam Khomeini (ra), vol.1, pg.279, question No.484, Islamic Publications Office, Qom, 5th edition, 2001; Imam Khomeini, Al-Rasail al-Ashr, pg.64, Institute for Preparation and Publication of the Works of Imam Khomeini, Qom, 1st Edition, 1420 A.H.
 - Answers to Jurisprudential Questions (Ajwebat al-Istifta’at) (Farsi version), pg.120, question No.599 and 600.
 - Khoei, Sayed Abul Qasim, Serat al-Najat (with connotation by Tabrizi), vol.3, pg.74, Al-Muntakhab Publication Office, qom, 1st edition, 1416 A.H.
 - Ibid.