The Kitáb-i-Aqdas - The Most Holy Book
Index term: Arab(s)
n192.
God hath laid hold on him who led thee astray.
A reference to Siyyid Muhammad-i-Isfahání, who is described by Shoghi Effendi as the "Antichrist of the Bahá'í Revelation". He was a man of corrupt character and great personal ambition who induced Mírzá Yahyá to oppose Bahá'u'lláh and to claim prophethood for himself (see note 190). Although he was an adherent of Mírzá Yahyá, Siyyid Muhammad was exiled with Bahá'u'lláh to 'Akká. He continued to agitate and plot against Bahá'u'lláh. In describing the circumstances of his death, Shoghi Effendi has written in God Passes By:

A fresh danger now clearly threatened the life of Bahá'u'lláh. Though He Himself had stringently forbidden His followers, on several occasions, both verbally and in writing, any retaliatory acts against their tormentors, and had even sent back to Beirut an irresponsible Arab convert, who had meditated avenging the wrongs suffered by his beloved Leader, seven of the companions clandestinely sought out and slew three of their persecutors, among whom were Siyyid Muhammad and Áqá Ján.
The consternation that seized an already oppressed community was indescribable. Bahá'u'lláh's indignation knew no bounds. "Were We", He thus voices His emotions, in a Tablet revealed shortly after this act had been committed, "to make mention of what befell Us, the heavens would be rent asunder and the mountains would crumble." "My captivity", He wrote on another occasion, "cannot harm Me. That which can harm Me is the conduct of those who love Me, who claim to be related to Me, and yet perpetrate what causeth My heart and My pen to groan."
q74.
 
Question: Concerning the definition of old age.
Answer: To the Arabs it denoteth the furthest extremity of old age, but for the people of Bahá it is from the age of seventy.