Temples

O people of the world! Build ye houses of worship throughout the lands in the name of Him Who is the Lord of all religions. Make them as perfect as is possible in the world of being, and adorn them with that which befitteth them, not with images and effigies. Then, with radiance and joy, celebrate therein the praise of your Lord, the Most Compassionate. Verily, by His remembrance the eye is cheered and the heart is filled with light.

Bahá’u’lláh, The Kitab-i-Aqdas, p. 29-30

The Bahá’í House of Worship is dedicated to the praise of God. The House of Worship forms the central edifice of the Mashriqu'l-Adhkar (the Dawning-place of the Praise of God), a complex which, as it unfolds in the future, will comprise in addition to the House of Worship a number of dependencies dedicated to social, humanitarian, educational, and scientific pursuits. ‘Abdu’l-Bahá describes the  Mashriqu'l-Adhkar as "one of the most vital institutions in the world", and Shoghi Effendi indicates that it exemplifies in tangible form the integration of "Bahá’í worship and service". Anticipating the future development of this institution, Shoghi Effendi envisages that the House of Worship and its dependencies "shall afford relief to the suffering, sustenance to the poor, shelter to the wayfarer, solace to the bereaved, and education to the ignorant". In the future, Bahá’í Houses of Worship will be constructed in every town and village.

Bahá’u’lláh, The Kitab-i-Aqdas, p. 190

Among the institutes of the Holy Books is that of the foundation of places of worship. That is to say, an edifice or temple is to be built in order that humanity might find a place of meeting, and this is to be conducive to unity and fellowship among them. The real temple is the very Word of God; for to it all humanity must turn, and it is the center of unity for all mankind. It is the collective center, the cause of accord and communion of hearts, the sign of the solidarity of the human race, the source of eternal life.

‘Abdu’l-Bahá, The Promulgation of Universal Peace, p. 65

In brief, the original purpose of temples and houses of worship is simply that of unity -- places of meeting where various peoples, different races and souls of every capacity may come together in order that love and agreement should be manifest between them. That is why Bahá’u’lláh has commanded that a place of worship be built for all the religionists of the world; that all religions, races and sects may come together within its universal shelter; that the proclamation of the oneness of mankind shall go forth from its open courts of holiness -- the announcement that humanity is the servant of God and that all are submerged in the ocean of His mercy. It is the Mashriqu'l-Adhkar. The world of existence may be likened to this temple and place of worship.

‘Abdu’l-Bahá, The Promulgation of Universal Peace, p. 65

Temples are the symbols of the divine uniting force so that when the people gather there in the House of God they may recall the fact that the law has been revealed for them and that the law is to unite them. They will realize that just as this temple was founded for the unification of mankind, the law preceding and creating it came forth in the manifest Word.

‘Abdu’l-Bahá, The Promulgation of Universal Peace, p. 65

The Mashriqu'l-Adhkar is one of the most vital institutions in the world, and it hath many subsidiary branches. Although it is a House of Worship, it is also connected with a hospital, a drug dispensary, a traveller's hospice, a school for orphans, and a university for advanced studies. Every Mashriqu'l-Adhkar is connected with these five things.

‘Abdu’l-Bahá, Selections from the Writings of ‘Abdu’l-Bahá, p. 99-100

The Bahá’í House of Worship is a nine-sided building, symbolic of the number of Bahá. Bahá’u’lláh has forbidden the display of pictures or statues within its walls and since there are no clergy in the Faith, there are to be no sermons. Another prohibition is the use of musical instruments. Only the human voice may be used in chanting or reading the word of God and glorifying his Name.

Adib Taherzadeh, The Revelation of Bahá’u’lláh v 3, p. 348