Baha’u’llah describes (in a prayer) the extreme hardships of “that terrible journey” from Tihran to Baghdad in 1853 and the “woes and trials” He endured in the Siyah-Chal (just prior to the journey)

In a prayer revealed by Him at that time [during the journey], Bahá'u'lláh, expatiating upon the woes and trials He had endured in the Siyah-Chal, thus bears witness to the hardships undergone in the course of that "terrible journey": "My God, My Master, My Desire!... Thou hast created this atom of dust through the consummate power of Thy might, and nurtured Him with Thine hands which none can chain up.... Thou hast destined for Him trials and tribulations which no tongue can describe, nor any of Thy Tablets adequately recount. The throat Thou didst accustom to the touch of silk Thou hast, in the end, clasped with strong chains, and the body Thou didst ease with brocades and velvets Thou hast at last subjected to the abasement of a dungeon. Thy decree hath shackled Me with unnumbered fetters, and cast about My neck chains that none can sunder. A number of years have passed during which afflictions have, like showers of mercy, rained upon Me.... How many the nights during which the weight of chains and fetters allowed Me no rest, and how numerous the days during which peace and tranquillity were denied Me, by reason of that wherewith the hands and tongues of men have afflicted Me! Both bread and water which Thou hast, through Thy all-embracing mercy, allowed unto the beasts of the field, they have, for a time, forbidden unto this servant, and the things they refused to inflict upon such as have seceded from Thy Cause, the same have they suffered to be inflicted upon Me, until, finally, Thy decree was irrevocably fixed, and Thy behest summoned this servant to depart out of Persia, accompanied by a number of frail-bodied men and children of tender age, at this time when the cold is so intense that one cannot even speak, and ice and snow so abundant that it is impossible to move." (Shoghi Effendi, God Passes By, p. 108)