What follows is my provisional translation (in other words, not official or authorized; see here for more) of a passage from a Tablet of Baháʼuʼlláh. The version of the Tablet on which this translation is based has been published in Asráru’l-Áthár, vol. 2, pp. 17–18.
In the original passage, Baháʼuʼlláh refers to Himself in the third person, but this has been changed to the first person in the following translation (with the exception of “this Wronged One”) to sound less stilted.
It is worth mentioning that Baháʼuʼlláh goes into further detail on the invasion of the Banú-Qurayzih in a separate and little-known Tablet, provisionally translated by Will McCants and styled by him as “the Tablet of Tribulations,” or Lawḥ-i-Baláyá. A draft version of that translation, along with an accompanying introduction, is available online here. This was later adapted for print publication; refer to William McCants, “Mirza Husayn ‘Ali Nuri, Baha’u’llah, Tablet of Tribulations (Lawḥ-i Balāyā),” Baha’i Studies Review, vol. 20, no. 1 (June 2014), pp. 87–95.
When I was but a child, this Wronged One read an account of the invasion of the Banú-Qurayẓih  recorded in a book attributed to the late Mullá Báqir Majlisí. From that very moment, I became so perplexed, and was stricken with such profound grief, that My pen is powerless to describe it—though what transpired during that event was the decree of God, and its only purpose was to annihilate the oppressors. Yet, as I beheld the limitless ocean of pardon and mercy surging before Me, I would, in those days, implore God—exalted be His glory—to bring about that which would foster love, fellowship, and unity amongst all the peoples of the earth until suddenly,  ere the break of dawn on the second day of the month of Muḥarram,  all My thoughts, My speech, and My demeanor were completely transformed. So intense was this transformation that I seemed to discern the joyful tidings of My ascension. For twelve consecutive days I remained in this transformed state; thereupon were the waves of the ocean of Mine utterance made manifest, and the splendors of the day-star of Mine assurance shone brilliantly. In this state I persisted, until at last it culminated in the moment of Revelation, whereupon I attained unto that which God hath made the source of the joy of all worlds, and the dawning-place of bounty unto all who are in heaven and on earth. Thereafter, through the agency of the Pen of the Most High, We removed, at Our irresistible and irrevocable bidding, all mention of whatsoever had been the cause of affliction, calamity, and strife, and have revealed only that which will conduce to concord and unity.
 “The Banū Qurayẓa were one of the three major Jewish tribes in pre-Islamic Medina (Yathrib). …. According to the Islamic sources…the Banū Qurayẓa, under the leadership of Kaʿb ibn Asad, struck a nonbelligerency treaty with Muḥammad shortly after his arrival in Medina in 622. When the enemies of the Muslims besieged Medina in 627, the leader of the already-exiled Banū Naḍir, Ḥuyyay ibn Akhṭab, convinced Kaʿb to violate the agreement and negotiate with the enemy. However, Muḥammad was able to undo the new alliance. With the departure of the enemy, Muḥammad attacked the Banū Qurayẓa for having violated the treaty. Besieged in their forts for nearly a month, they ultimately surrendered unconditionally, placing their fate in the hands of Saʿd ibn Muʿādh, with whom they had a preexisting alliance. Saʿd turned against them. Trenches were dug and the men, numbering somewhere between four hundred and nine hundred, were marched out, executed, and buried as Muḥammad watched. The women, children, and under-age boys were sold into slavery or distributed as gifts” (Shari Lowin, “Banū Qurayẓa,” Encyclopedia of Jews in the Islamic World, pp. 338–339.)
 Notably, the word baghtatan (“suddenly”) is absent from the version of this Tablet published in Ishráq-Khávarí, Máʼidiy-i-Ásmáni 7:135–37, but this is an error. In addition to baghtatan being present in the version published in Asráru’l-Áthár 2:17–18 (the source text for this translation), and also in INBA 81:159, the Research Department has stated that “the original manuscript of this Tablet includes the word baghtatan” (Memorandum dated 15 January 2020 and addressed to the Universal House of Justice; private correspondence with Bijan Masumian, who was copied on this memorandum).
 Literally, “the month of [My] birth,” in the original Persian text.
A typescript of the complete text of this Tablet appears below.