What follows is my provisional translation (in other words, not official or authorized; see here for more) of a Tablet of ‘Abdu’l-Bahá. The original text has not been published; Farhan Yazdani kindly shared this scan of a handwritten copy with me. A few biographical details about Raḍa’r-Rúḥ are published in Adib Taherzadeh, The Revelation of Bahá’u’lláh, vol. 1, pp. 84–85, available online here.
Delivered via Mírzá Yúnis Khán [Afrúkhtih]
To the descendants of the esteemed Raḍa’r-Rúḥ—Raḍíu’lláh Khán, Zarrín-Táj, and Rúḥangíz—upon him and upon them be the Glory of God, the All-Glorious
He is God
O remnants of the honorable Raḍa’r-Rúḥ! Although that leader of the righteous ones hath returned to the refuge of divine Providence, praised be God that you all persist as tokens of his memory; hence, ye are exceedingly precious in the estimation of ‘Abdu’l-Bahá. That soul faced dire calamities on this Path; every day he drank a draught from the cup of affliction. Not for a single night did he rest in comfort on his bed, neither on any morning did he enjoy peace of heart and serenity of soul. At all times was he the object of tribulation and the target of the shaft of oppression. My hope is such that you all may cause his mention to be exalted, and that you may water the field he hath sown, in order that ye may be showered with the loving-kindness of ‘Abdu’l-Bahá and bring about his happiness.
Upon you be the Glory of the All-Glorious.
A typescript of the original Persian text of this Tablet appears below (all punctuation mine).