Baha’u’llah’s Tablet to Ashraf is a pastoral letter for Siyyid Ashraf-i Zanjani, who was staying with Baha’u’llah and was subsequently martryed.
Ashraf was born during the siege of Zanjan, Iran, in 1850, where 2000 Babis held a section of the town against the forces of the town’s governor. Ashraf’s father was killed there and his mother, subsequently, raised him and his two sisters alone. When Ashraf was a young man, he twice made the long journey from Zanjan, Iran, to Edirne, Turkey, to visit Baha’u’llah. On the second occasion, Baha’u’llah wrote this tablet for him.
Taherzadeh gives the details of Ashraf’s life in the second volume of his Revelation of Baha’u’llah series. He says that Ashraf’s visit with Baha’u’llah was cut short suddenly when Baha’u’llah instructed Ashraf to return home. A reference to this can be found about halfway through the tablet, where Baha’u’llah says to Ashraf: “Know that the time has come for your sojourn before the throne to end”. The explanation Taherzadeh gives for this is that, at the time of the visit, Ashraf’s mother was being subjected to huge pressure back home from relatives about her raising her children as Baha’is. She became so upset by this that she begged Baha’u’llah in prayer to send her children (Ashraf and his sister) home, which he did. Ashraf was reportedly so angry about this that he likened the action of his mother to the sin of Adam.
Not long after Ashraf returned home, he was martyred, along with his best friend Aba Basir. The scene of his martyrdom is described in a passage in Gleanings (LXIX) where Baha’u’llah recounts the story of “Ashraf’s mother”, who was called to the scene of her son’s imminent martyrdom in the hope that she would convince him to recant. Instead, she insisted that he give up his life.
Tablet to Ashraf falls roughly into two sections. The first section runs from the beginning through to the paragraph, about halfway through, starting “O Ashraf! Give thanks to God inasmuch as He has honored you with meeting Him…” In the first section, Baha’u’llah outlines some of the extraordinary and unique characteristics of his revelation, with the seeming intention of showing how great is the measure of bounty that the revelation has showered on creation. Early on, Baha’u’llah explains that, with this revelation, God has appeared to all things in the splendour of all the names and attributes of God and anything can attain to the Greatest Name if it is completely detached from creation. Again, if all things begged the Lord, in a spirit of complete detachment, for the treasures of heaven and earth, this would be instantly granted to them.
Baha’u’llah explains that the Book (of revelation) has been sent down in the person of Baha’u’llah (“this youth”) and counsels people not to run away from him. He makes the crucial point that his first proof is his own self – that is, the person of the youth. He himself is the first proof of the station he claims to have. His second proof is what he reveals or manifests, and then in third place are his verses. He likens himself, his greatest proof, to the sun and points out that even the blind can recognise it, just as a blind person can feel the warmth of the sun’s rays. He says that the Sun of his self is the same reality as the Fire that Moses saw on Sinai, which is always declaring “There is no God besides Me, the Powerful, the Most High!”
It is instructive to compare Baha’u’llah’s explanations about his self in this tablet with his comments in Lawh-i Tawhid (Tablet of Divine Unity), where he presents the same idea in a different, but related, way. For example, in Lawh-i Tawhid, Baha’u’llah likens his teaching that people should recognise his self to the process of recognising any other person. If we recognise that person by their clothes, we will not recognise them again when they put on different clothes. Therefore, we must recognise Baha’u’llah by his self and not by what issues from him, because that may change and is not really him anyway.
Finally, in the first section of the Tablet to Ashraf, Baha’u’llah makes the point that, in order to see the Sun of his self, a person must look with their own eyes. God has created every person in such as way that they can do this of their own accord. This faculty in each person ensures that everyone is in a position to understand God’s proof and accept it if they choose to. Baha’u’llah states that God is not unjust and so does not ask a person to do something they cannot do. Again, this theme is discussed in Lawh-i Tawhid. In that tablet, Baha’u’llah emphasises the responsibility each person has of examining Baha’u’llah’s claim for themselves and makes the very important point that a person’s acceptance or denial of the revelation cannot be based on the opinions of others.
“In like manner, every servant must take it upon himself to recognize that Orb of Unity. Therefore, the denial or acceptance of His servants hath never been, nor will it ever be, sufficient proof for any one to embrace or reject Him.” 
The second section of Tablet to Ashraf starts at “O Ashraf! Give thanks to God inasmuch as He has honored you with meeting Him and permitted you to enter His presence, the seat of sublime glory.” With these words, Baha’u’llah begins his personal address to Ashraf, which runs to the end. This section also contains messages for two other named individuals: Muhammad ‘Ali and Aba Basir. In both cases, Baha’u’llah gives them similar advice to what he gives to Ashraf. Aba Basir is known to be Aqa Naqd-’Ali, who was blind. Baha’u’llah gave him the title “Basir”, meaning “Seeing”. He was Ashraf’s close friend and was beheaded just before Ashraf was killed. The name Muhammad ‘Ali probably refers to Aqa Mirza Muhammad ‘Aliy-i-Tabib, who was also from Zanjan and died a martyr. Baha’u’llah wrote a tablet of visitation jointly for these three men – Siyyid Ashraf, Aba Basir and Muhammad ‘Ali.
The second section of the tablet begins with Baha’u’llah telling Ashraf that it is time to leave and instructing him on what to do. He is to take the tablet and visit the believers in Iran. He is to tell them what has happened to Baha’u’llah and give them the glad tidings of the revelation. Baha’u’llah is particularly concerned that Ashraf tell the believers back home about the difficulties Baha’u’llah faced while living in Edirne. He does not mention his half-brother, Azal, by name, but states explicitly that Ashraf is to tell the believers about the attempt to kill him and the subsequent scheming against him, which was carried out by Azal and his sympathisers. At this time, the believers in Iran were confused about Azal, who was reportedly the leader of the Babis, but were unaware of his cruelty towards Baha’u’llah. Baha’u’llah counsels the believers not to listen to the words of those who have been unfaithful to him and have schemed against him. He reminds them of the inevitable moment when they will stand before him and face the consequences of their actions. He warns them not to be the sort of people who believe in something and then give it away. He repeatedly emphasises the need for everyone to be detached from all things, focus on what he has told them and remember their Lord.
 See Adib Taherzadeh: The Revelation of Baha’u’llah. Adrianople 1863-68, vol 2, pp 223-230.
 Further details about the tablet can be found in Revelation of Baha’u’llah, vol 2, pp 230-232.
 “Say: O people! The Book of God has now appeared in the person of this youth. Blessed, therefore, be God, the most excellent of makers!”
 Lawh-i Tawhid (Tablet of Divine Unity), translated by Shoghi Effendi and Adib Masumian https://adibmasumian.com/translations/lawh-i-tawhid/
 The details about Aqa Naqd-‘Ali (Aba Basir) and Aqa Mirza Muhammad ‘ Aliy-i Tabib come from Revelation of Baha’u’llah, vol 2, pp 226-7 and 229. Baha’u’llah also mentions Aba Basir, and his martyrdom with Ashraf, in Epistle to the Son of the Wolf, pp 73-4.