What follows is my provisional translation (in other words, not official or authorized; see here for more) of a Tablet from Bahá’u’lláh, the original text of which is published in Risáliy-i-Tasbíḥ va Tahlíl, pp. 203–204.
He is the Most Holy, the Most Great, the Most Glorious
Praise be unto Him Who hath manifested Himself of His own volition. He is, in truth, the Almighty, the Help in Peril, the Self-Subsisting.
These are the Ayyám-i-Há, the days in which We have enjoined everyone to be generous unto themselves, and unto such as have set their faces towards this transcendent station. Make ye mention of God in these days, and know ye their value, inasmuch as every one of these days recounteth this Name, through which God hath subdued all things visible and invisible. We have, as a token of Our grace, set these days to occur before the Fast. I, verily, am powerful over all that hath been and shall be. Blessed is he who observeth that whereunto he hath been bidden by God, and woe betide the wayward and the outcast.
We have revealed these verses and have sent them unto thee in this holy, this glorious day, that thou mayest render thanks unto thy Lord God, and offer Him such fervent praise as would awaken them that are fast asleep.
A scanned copy of the complete Arabic text of this Tablet appears below.