“The process” that Bahá’u’lláh’s banishment from Persia “set in motion”

The process which it set in motion, gradually progressing and unfolding, began by establishing His Cause for a time in the very midst of the jealously-guarded stronghold of Shí‘ah Islám, and brought Him in personal contact with its highest and most illustrious exponents; then, at a later stage, it confronted Him, at the seat of the Caliphate, with the civil and ecclesiastical dignitaries of the realm and the representatives of the Sultán of Turkey, the most powerful potentate in the Islamic world; and finally carried Him as far as the shores of the Holy Land, thereby fulfilling the prophecies recorded in both the Old and the New Testaments, redeeming the pledge enshrined in various traditions attributed to the Apostle of God and the Imáms who succeeded Him, and ushering in the long-awaited restoration of Israel to the ancient cradle of its Faith. 

- Shoghi Effendi  (‘God Passes By’)

The opening of “a new and glorious chapter in the history of the first Bahá’í century”, “unparalleled in the religious annals of the entire human race”

The Sháh’s edict, equivalent to an order for the immediate expulsion of Bahá’u’lláh from Persian territory, opens a new and glorious chapter in the history of the first Bahá’í century. Viewed in its proper perspective it will be even recognized to have ushered in one of the most eventful and momentous epochs in the world’s religious history. It coincides with the inauguration of a ministry extending over a period of almost forty years—a ministry which, by virtue of its creative power, its cleansing force, its healing influences, and the irresistible operation of the world-directing, world-shaping forces it released, stands unparalleled in the religious annals of the entire human race. It marks the opening phase in a series of banishments, ranging over a period of four decades, and terminating only with the death of Him Who was the Object of that cruel edict. 

- Shoghi Effendi  (‘God Passes By’)

Years later Bahá’u’lláh confirmed the offer of assistance that He received from a Russian minister in Tihran

“Whilst I lay chained and fettered in the prison,” He Himself, years after, testified in His Epistle addressed to the Czar of Russia, Nicolaevitch Alexander II, “one of thy ministers extended Me his aid. Whereupon God hath ordained for thee a station which the knowledge of none can comprehend except His knowledge. Beware lest thou barter away this sublime station.” “In the days,” is yet another illuminating testimony revealed by His pen, “when this Wronged One was sore-afflicted in prison, the minister of the highly esteemed government (of Russia)—may God, glorified and exalted be He, assist him!—exerted his utmost endeavor to compass My deliverance. Several times permission for My release was granted. Some of the ‘ulamás of the city, however, would prevent it. Finally, My freedom was gained through the solicitude and the endeavor of His Excellency the Minister.… His Imperial Majesty, the Most Great Emperor—may God, exalted and glorified be He, assist him!—extended to Me for the sake of God his protection—a protection which has excited the envy and enmity of the foolish ones of the earth.” 

- Shoghi Effendi  (Quoting  Bahá’u’lláh in 'God Passes By’)

Russia expressed the desire to take Bahá’u’lláh under its protection

The Russian Minister, as soon as he was informed of the Imperial decision, expressed the desire to take Bahá’u’lláh under the protection of his government, and offered to extend every facility for His removal to Russia. This invitation, so spontaneously extended, Bahá’u’lláh declined, preferring, in pursuance of an unerring instinct, to establish His abode in Turkish territory, in the city of Baghdád. 

- Shoghi Effendi  (‘God Passes By’)

Upon leaving the Síyáh-Chál Bahá’u’lláh received a decree from Násiri’d-Dín Sháh to leave the country in one month

The relative peace and tranquillity accorded Bahá’u’lláh after His tragic and cruel imprisonment was destined, by the dictates of an unerring Wisdom, to be of an extremely short duration. He had hardly rejoined His family and kindred when a decree from Násiri’d-Dín Sháh was communicated to Him, bidding Him leave the territory of Persia, fixing a time-limit of one month for His departure and allowing Him the right to choose the land of His exile. 

- Shoghi Effendi  (‘God Passes By’)

Upon Bahá’u’lláh’s release from the Síyáh-Chál, the Grand Vizir heeded Bahá’u’lláh’s advice and commanded the governors of the realm to put a halt on the persecution of the Bábís

No sooner had He presented Himself before them than the Grand Vizir addressed Him saying: “Had you chosen to take my advice, and had you dissociated yourself from the Faith of the Siyyid-i-Báb, you would never have suffered the pains and indignities that have been heaped upon you.” “Had you, in your turn,” Bahá’u’lláh retorted, “followed My counsels, the affairs of the government would not have reached so critical a stage.” Mírzá Áqá Khán was thereupon reminded of the conversation he had had with Him on the occasion of the Báb’s martyrdom, when he had been warned that “the flame that has been kindled will blaze forth more fiercely than ever.” “What is it that you advise me now to do?” he inquired from Bahá’u’lláh. “Command the governors of the realm,” was the instant reply, “to cease shedding the blood of the innocent, to cease plundering their property, to cease dishonoring their women, and injuring their children.” That same day the Grand Vizir acted on the advice thus given him; but any effect it had, as the course of subsequent events amply demonstrated, proved to be momentary and negligible. 

- Shoghi Effendi  (‘God Passes By’)