surnamed Áqáy-i-Kalím was the only true brother of Bahá’u’lláh
. He was later identified by Shoghi Effendi
as one of the nineteen Apostles of Bahá’u’lláh
. The life of Mírzá Músá was so inextricably bound up with that of Bahá’u’lláh
himself, that his life and background mirror the life and travels of Bahá’u’lláh. He was an integral part of correspondence between Bahá’u’lláh and the Bahá’ís. He experienced the same imprisonment, exile, assaults, and degrading circumstances that were given to the small band of family members associated with Bahá’u’lláh and ‘Abdu’l-Bahá
. Bahá’u’lláh used Mírzá Músá as an example to show his respect for the law. In the history of the Bahá’í cause, Mírzá Músá stands out as a loyal and faithful follower until the end.