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 revealed in commemoration of the Nineteen-Day Fast. The original text of this passage has been published in Ḥadíqiy-i-ʻIrfán, p. 126.
He is God, exalted be He, the Lord of majesty and power
These days are the days of fasting, and the dawning-place of the evidences of the grace of God. Fasting reduceth carnal inclinations, and increaseth spiritual tendencies; it transmuteth sensual desire into divine guidance, and turneth disloyalty into faithfulness. It is the most potent medicine, the greatest remedy, for the edification of the self. In it lie hidden sundry wisdoms, and manifold benefits as yet untold. Exalted is He Who hath bidden men to observe it! Magnified is He Who hath enjoined it upon them! Blessings and salutations be upon Him through Whom the commandments of God have been revealed—He through Whom the ordinances of God have been propagated, the bounty of His knowledge sent down, and the tokens of His favors disclosed—and upon His kindred and companions, through whom God hath illumined the horizons of His countries, and demonstrated His ascendancy over His servants…
A typed version of the Persian and Arabic text of this passage appears below (all punctuation and vocalization mine).