The Kitáb-i-Aqdas - The Most Holy Book
Index term: Mosque(s)
n19.
Save in the Prayer for the Dead, the practice of congregational prayer hath been annulled.
Congregational prayer, in the sense of formal obligatory prayer which is to be recited in accordance with a prescribed ritual as, for example, is the custom in Islám where Friday prayer in the mosque is led by an imám, has been annulled in the Bahá'í Dispensation. The Prayer for the Dead (see note 10) is the only congregational prayer prescribed by Bahá'í law. It is to be recited by one of those present while the remainder of the party stands in silence; the reader has no special status. The congregation is not required to face the Qiblih (Q&A 85).
The three daily Obligatory Prayers are to be recited individually, not in congregation.
There is no prescribed way for the recital of the many other Bahá'í prayers, and all are free to use such non-obligatory prayers in gatherings or individually as they please. In this regard, Shoghi Effendi states that

. . . although the friends are thus left to follow their own inclination, . . . they should take the utmost care that any manner they practise should not acquire too rigid a character, and thus develop into an institution. This is a point which the friends should always bear in mind, lest they deviate from the clear path indicated in the Teachings.
n116.
O Emperor of Austria! He Who is the Dayspring of God's Light dwelt in the prison of 'Akká at the time when thou didst set forth to visit the Aqsá Mosque.
Francis Joseph (Franz Josef, 1830-1916), Emperor of Austria and King of Hungary, made a pilgrimage to Jerusalem in 1869. While in the Holy Land he failed to take the opportunity to inquire about Bahá'u'lláh Who at that time was a prisoner in 'Akká (Acre).
The Aqsá Mosque, literally, the "Most Distant" Mosque, is referred to in the Qur'án, and has become identified with the Temple Mount in Jerusalem.
q94.
 
Question: Concerning mosques, chapels and temples.
Answer: Whatever hath been constructed for the worship of the one true God, such as mosques, chapels and temples, must not be used for any purpose other than the commemoration of His Name. This is an ordinance of God, and he who violateth it is verily of those who have transgressed. No harm attacheth to the builder, for he hath performed his deed for the sake of God, and hath received and will continue to receive his just reward.
q94.
 
Question: Concerning mosques, chapels and temples.
Answer: Whatever hath been constructed for the worship of the one true God, such as mosques, chapels and temples, must not be used for any purpose other than the commemoration of His Name. This is an ordinance of God, and he who violateth it is verily of those who have transgressed. No harm attacheth to the builder, for he hath performed his deed for the sake of God, and hath received and will continue to receive his just reward.