As to the Nineteen Day festivity, it is of the utmost importance that the friends should gather at a meeting where, in complete attunement and love, they should engage in the remembrance of God and His praise, and converse as to the glad tidings of God, and proofs of the Advent of Bahá’u’lláh, and should recount the high deeds and sacrifices of the lovers of God in Persia, and tell of the martyrs' detachment from the world, and their ecstasy, and of how the believers there stood by one another and gave up everything they had.

‘Abdu’l-Bahá, The Compilation of Compilations vol. I, p. 427

Give ye great weight to the Nineteen Day gatherings, so that on these occasions the beloved of the Lord and the handmaids of the Merciful may turn their faces toward the Kingdom, chant the communes, beseech God's help, become joyfully enamored each of the other, and grow in purity and holiness, and in the fear of God, and in the resistance to passion and self. Thus will they separate themselves from this elemental world, and immerse themselves in the ardors of the spirit."

‘Abdu’l-Bahá, Developing Distinctive Bahá’í Communities, Section 9.16

Music, as one of the arts, is a natural cultural development, and the Guardian does not feel that there should be any cultivation of "Bahá’í Music" any more than we are trying to develop a Bahá’í school of painting or writing. The believers are free to paint, write and compose as their talents guide them. If music is written, incorporating the sacred writings, the friends are free to make use of it, but it should never be considered a requirement at Bahá’í meetings to have such music. The further away the friends keep from any set forms, the better, for they must realize that the Cause is absolutely universal, and what might seem a beautiful addition to their mode of celebrating a Feast, etc., would perhaps fall on the ears of people of another country as unpleasant sounds -- and vice versa. As long as they have music for its own sake it is all right, but they should not consider it Bahá’í music.

Shoghi Effendi, The Importance of the Arts in Promoting the Faith

The Writings of the Báb and Bahá’u’lláh can certainly be read any time at any place; likewise the Writings of ‘Abdu’l-Bahá are read freely during the spiritual part of the Feast. The Guardian has instructed that during the spiritual part of the Feast, his own writings should not be read. In other words, during the spiritual part of the Feast, readings should be confined to the Writings of the Báb, Bahá’u’lláh and to a lesser extent of the Master; but during the part of the Feast the Guardian's writings should not be read. During the administrative discussion of the Feast, then the Guardian's writings may be read. Of course, during the administrative part of the Feast there can be no objection to the reading of the writings of the Báb, Bahá’u’lláh or ‘Abdu’l-Bahá.

Shoghi Effendi, Lights of Guidance, p. 245

There is a time set aside at the Nineteen Day Feasts for the community to express its views and make suggestions to its assembly; the assembly and the believers should look forward to this happy period of discussion, and neither fear it nor suppress it.

Shoghi Effendi, NSA USA - Developing Distinctive Bahá’í Communities

But it is not only in the sense of its gradual unfoldment as an institution that the evolution of the Feast must be regarded; there is a broader context yet. The Feast may well be seen in its unique combination of modes as the culmination of a great historic process in which primary elements of community life acts of worship, of festivity and other forms of togetherness over vast stretches of time have achieved a glorious convergence. The Nineteen Day Feast represents the new stage in this enlightened age to which the basic expression of community life has evolved. Shoghi Effendi has described it as the foundation of the new World Order, and in a letter written on his behalf, it is referred to as constituting "a vital medium for maintaining close and continued contact between the believers themselves, and also between them and the body of their elected representatives in the local community.

Universal House of Justice, 27 August 1989 to the Followers of Bahá’u’lláh in Every Land