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. 213–215.
There is a special heading accompanying this Tablet where it appears in the above compilation, which indicates that the Tablet is meant to be recited by whoever wishes to be visited by Bahá’u’lláh in his or her dreams.
According to the Leiden List, this Tablet “was revealed for one ‘Riḍá’, separated from Bahá’u’lláh, whose household included a woman related (married?) to one of the exiles.”
He is God, the Almighty
This is the utterance of God as spoken in the Tree of Separation:
Be patient, O loved ones of God, and take heed that ye not be neglectful in your remembrance of Us. Remember ye, with love in your hearts, the time we spent together. Say: The Beauty of the Spirit hath been obscured, and for this every eye hath wept sore, and every heart been consumed.
As for thee, O Riḍá, remember My days, and call thou to mind the melodies and warblings of this glorious, this beloved Bird. Reflect thou, then, upon the days of the Spirit —how He appeared in your midst and lived among you but for a few years. Protect thyself, and keep safe them that are in thy home, be they man or woman. Know thou, then, that We have made this Tablet even as a garment unto thee, that from it thou mayest inhale the fragrances of God—the Almighty, the Best-Beloved—and that We have wafted from this garment the sweet savours of grace upon all who have been brought into the realm of existence. Well is it with them that have been exposed to these fragrances, and have detected therefrom that which shall prompt them to turn their faces towards the Realm of conspicuous glory.
Whoso reciteth this Tablet with the love of his Lord in his heart shall behold in his dream that which he hath desired from the Presence of God, the All-Glorious, the Well-Beloved. Thus have We once again deigned to bestow upon thee a token of Our favour, that thou mayest be content with Me and with thyself in these days, whose import even them that are nigh unto God have failed to apprehend.
Give Our remembrance to everyone in thy home, that they may gather together beneath the banner of the Cause, and that the love of God may be manifested among you. Show thou, moreover, kindness unto she whom God hath joined together with the one who hath, with his servant, abandoned his home. Thus have We exhorted you in truth, if ye be of them that comprehend.
May the Spirit  be ever with you, and with them that place their trust and confidence in their Lord.
 This reference is unclear. The original Arabic word translated here as “Spirit,” rúḥ, typically refers to Jesus Christ in the Baháʼí Writings when it is used as a proper noun, but that interpretation doesn’t seem to make sense in this context. Historically speaking, it might be more sensible to interpret it as a reference to the Báb. After all, there are several parallels drawn between the lives of Jesus and the Báb in Baháʼí literature (cf. Shoghi Effendi, God Passes By, pp. 56ff; H.T.D. Rost, The Gates and the King of Glory: A Comparative Study of the Lives of Jesus Christ and the Báb; etc.). Alternatively, it could also be read as a reference to Baháʼu’lláh Himself. At this point, Baháʼu’lláh had been separated from Riḍá—the recipient of this Tablet—so perhaps this is Baháʼu’lláh’s way of instructing Riḍá to remember the days when they were still in each other’s company. It would probably be easier to resolve this question if more details were known about Riḍá and the circumstances attending the revelation of this Tablet.
 Similarly unclear for the reasons given in note #1. Perhaps a reference to the Holy Spirit?
A scanned copy of the complete Arabic text of this Tablet appears below.