The Kitáb-i-Aqdas - The Most Holy Book
Index term: House of Justice, National (Secondary)
n49.
The Lord hath ordained that in every city a House of Justice be established
The institution of the House of Justice consists of elected councils which operate at the local, national and international levels of society. Bahá'u'lláh ordains both the Universal House of Justice and the Local Houses of Justice in the Kitáb-i-Aqdas. 'Abdu'l-Bahá, in His Will and Testament, provides for the Secondary (National or Regional) Houses of Justice and outlines the method to be pursued for the election of the Universal House of Justice.
In the verse cited above, the reference is to the Local House of Justice, an institution which is to be elected in a locality whenever there are nine or more resident adult Bahá'ís. For this purpose, the definition of adult was temporarily fixed at the age of 21 years by the Guardian, who indicated it was open to change by the Universal House of Justice in the future.
Local and Secondary Houses of Justice are, for the present, known as Local Spiritual Assemblies and National Spiritual Assemblies. Shoghi Effendi has indicated that this is a "temporary appellation" which,

. . . as the position and aims of the Bahá'í Faith are better understood and more fully recognized, will gradually be superseded by the permanent and more appropriate designation of House of Justice. Not only will the present-day Spiritual Assemblies be styled differently in future, but they will be enabled also to add to their present functions those powers, duties, and prerogatives necessitated by the recognition of the Faith of Bahá'u'lláh, not merely as one of the recognized religious systems of the world, but as the State Religion of an independent and Sovereign Power.
n50.
the number of Bahá
The abjad numerical equivalent of "Bahá" is nine. The Universal House of Justice and the National and Local Spiritual Assemblies currently have nine members each, the minimum number prescribed by Bahá'u'lláh.
n51.
It behoveth them to be the trusted ones of the Merciful among men
The general powers and duties of the Universal House of Justice, the National Spiritual Assemblies and the Local Spiritual Assemblies and the qualifications for membership are set forth in the Writings of Bahá'u'lláh and 'Abdu'l-Bahá, in the letters of Shoghi Effendi, and in the elucidations of the Universal House of Justice. The major functions of these institutions are outlined in the Constitution of the Universal House of Justice, and in those of the National and Local Spiritual Assemblies.
n80.
O ye Men of Justice!
It has been elucidated in the writings of 'Abdu'l-Bahá and Shoghi Effendi that, while the membership of the Universal House of Justice is confined to men, both women and men are eligible for election to Secondary and Local Houses of Justice (currently designated as National and Local Spiritual Assemblies).
n183.
O ye the learned ones in Bahá
Bahá'u'lláh eulogizes the learned among His followers. In the Book of His Covenant, He wrote: "Blessed are the rulers and learned among the people of Bahá." Referring to this statement, Shoghi Effendi has written:

In this holy cycle the "learned" are, on the one hand, the Hands of the Cause of God, and, on the other, the teachers and diffusers of His Teachings who do not rank as Hands, but who have attained an eminent position in the teaching work. As to the "rulers" they refer to the members of the Local, National and International Houses of Justice. The duties of each of these souls will be determined in the future.

The Hands of the Cause of God were individuals appointed by Bahá'u'lláh and charged with various duties, especially those of protecting and propagating His Faith. In Memorials of the Faithful 'Abdu'l-Bahá referred to other outstanding believers as Hands of the Cause, and in His Will and Testament He included a provision calling upon the Guardian of the Faith to appoint Hands of the Cause at his discretion. Shoghi Effendi first raised posthumously a number of the believers to the rank of Hands of the Cause, and during the latter years of his life appointed a total of 32 believers from all continents to this position. In the period between the passing of Shoghi Effendi in 1957 and the election of the Universal House of Justice in 1963, the Hands of the Cause directed the affairs of the Faith in their capacity as Chief Stewards of Bahá'u'lláh's embryonic World Commonwealth (see note 67). In November 1964, the Universal House of Justice determined that it could not legislate to make it possible to appoint Hands of the Cause. Instead, by a decision of the House of Justice in 1968, the functions of the Hands of the Cause in relation to protecting and propagating the Faith were extended into the future by the creation of the Continental Boards of Counsellors, and in 1973 through the establishment of the International Teaching Centre, which has its seat in the Holy Land.
The Universal House of Justice appoints the Counsellor members of the International Teaching Centre and the Continental Counsellors. Members of Auxiliary Boards are appointed by the Continental Counsellors. All these individuals fall within the definition of the "learned" given by Shoghi Effendi in the statement quoted above.