Mirza Aqa Jan embraced the religion of the Báb when he was about sixteen years old and became instantly “aflame with devotion.” He was neither learned nor rich and made his living in his hometown of Kashan making and selling soap. Soap-making was a humble trade in those days, often carried out at home by people who were not well educated.
Mirza Aqq jan was also a seeker of truth who had seen the Báb in his dreams and believed in Him. He had also read the Writings of Bahá’u’lláh and felt the urge to attain His presence. He left his home in Kashan unexpectedly and traveled to Iraq.
When he reached Baghdad, he learned that Bahá’u’lláh was visiting the Babís in the neighboring town of Karbila and where He was the guest of one of the resident Bábis. This was before Baha’u’llah’s Declaration in the Garden of Ridvan. Mirza Aqa Jan followed Baha’u’llah to Karbila.
Bahá’u’lláh liked to spend the hot summer nights on the flat roof of the house, as people often did. There He chanted His prayers under a canopy of stars and slept in the fresh night air.
One night Bahá’u’lláh invited Mirza Aqa Jan who had just arrived in Karbala to join Him on the roof. Bahá’u’lláh was already sleeping when Mirza Aqa jan spread out his bedding nearby on a carpet and lay down for a brief rest.
Many years later, Mirza Aqa jan related the following amazing account to the great Baha’i historian, Nabil:
"As it was summer-time, Bahá'u'lláh was in the habit of passing His evenings and of sleeping on the roof of the House.... That night, when He had gone to sleep, I, according to His directions, lay down for a brief rest, at a distance of a few feet from Him. No sooner had I risen, and ... started to offer my prayers, in a corner of the roof which adjoined a wall, than I beheld His blessed Person rise and walk towards me. When He reached me He said: 'You, too, are awake.' Whereupon He began to chant and pace back and forth. How shall I ever describe that voice and the verses it intoned, and His gait, as He strode before me! Methinks, with every step He took and every word He uttered thousands of oceans of light surged before my face, and thousands of worlds of incomparable splendor were unveiled to my eyes, and thousands of suns blazed their light upon me! In the moonlight that streamed upon Him, He thus continued to walk and to chant. Every time He approached me He would pause, and, in a tone so wondrous that no tongue can describe it, would say: 'Hear Me, My son. By God, the True One! This Cause will assuredly be made manifest. Heed thou not the idle talk of the people of the Bayán, who pervert the meaning of every word.' In this manner He continued to walk and chant, and to address me these words until the first streaks of dawn appeared.... Afterwards I removed His bedding to His room, and, having prepared His tea for Him, was dismissed from His presence." (Shoghi Effendi, ‘God Passes By’)
The Guardian refers to Mirza Aqa Jan as "the first to believe" Bahá’u’lláh as ‘Him Whom God shall make manifest’. He further indicates that:
“The confidence instilled in Mirza Aqa Jan by this unexpected and sudden contact with the spirit and directing genius of a new-born Revelation stirred his soul to its depths -- a soul already afire with a consuming love born of his recognition of the ascendancy which his newly-found Master had already achieved over His fellow-disciples in both Iraq and Persia. This intense adoration … informed his whole being, and … could neither be suppressed nor concealed…” (Shoghi Effendi, ‘God Passes By’)
From that night on, Mirza Aqa Jan knew with certainty that Baha'u'llah was the Promised One sent by God. He wanted nothing more than to remain in the presence of Bahá’u’lláh and to serve Him.
The other Bábís of Karbala did not see the "thousands of oceans of
light" that Mirza Aqa Jan saw. They saw only that Mirza Aqa Jan began
to treat Bahá’u’lláh with even greater reverence and devotion than before.
They were not surprised. People all around loved and admired Bahá’u’lláh.
Bahá’u’lláh chose Mirza Aqa Jan as His personal servant and gave him the title of Khadim (servant), and later Khadimu'llah (servant of God). At the same time that Mirza Aqa Jan was the 'servant in attendance', he was empowered by Bahá'u'lláh to act as His amanuensis in spite of his inadequate education. For the next forty years Mirza Aqa Jan would serve Baha'u'llah, writing down the divine tablets He revealed and the letters He dictated, and sending them to believers near and far. This he did till the end of the Ministry of Bahá'u'lláh. He served Bahá'u'lláh assiduously for those 40 years in the triple functions of secretary, servant and companion.
(Adapted from ‘God Passes By’, by Shoghi Effendi, ‘The Story of Bahá’u’lláh’, by Druzelle Cederquist, ‘The Covenant of Bahá’u’lláh’, by Adib Taherzadeh)