Deciphering the Signs of God: A Phenomenological Approach to Islam. Annemarie Schimmel. Albany: State University of New York Press, 1994. Pages 50-51, 81, 188-89.
...The door opens into the sacred space, and the Muslim knows that 'God is the Opener of the doors', mufattih al-abwab,
as He is called in a favourite invocation, for it is He who can open the doors of His mercy or generosity, not forgetting the gates of Paradise. In later Sufism, the seven principal Divine Names are even called hadana,
'doorkeepers'. Metaphorically, the concept of the door or gate is important by its use in the well-known hadith
deeply loved especially in Shia tradition, in which the Prophet states: 'I am the city of wisdom and 'Ali is its gate' (AM
no. 90), that is, only through 'All's mediation can one understand the Prophet's true teaching. As the gate, bab,
can be the person through whom the believer may be led into the Divine presence, it is logical that the spiritual guide could also be considered, or consider himself, to be The Gate, the Bab.
This claim was voiced most prominently by Mirza Muhammad 'Ali of Tabriz, which led to the emergence of a new religious movement, Babism, in early nineteenth-century Iran...
...Nineteen is the numerical value of the word wahid,
'One', and therefore highly appreciated; it is the sacred number of the Bahais. But also it plays a role in general Islam, not only because of the nineteen henchmen of Hell (Sura 74:30), but also because many interpreters connected it with the number of letters in the basmalah
(others, however, counted only eighteen letters in this formula). And in Shia speculation it occupied a prominent place as it is the sum of the twelve zodiacal signs and the seven planets, which correspond to the seven prophets and twelve imams. But when a Muslim, a few years ago, tried to prove with the help of a computer that the entire structure of the Koran relied upon Nineteen his work was met with great mistrust, even hatred...
The designation of Muhammad as the 'Seal of the prophets' included for
Muslim theologians the impossibility of the appearance any other religion and a Divinely-inspired shari'a
after Muhammad's death. Movements that claimed a continuing revelation, such as the Babi-Bahai movement in Iran at the beginning of the nineteenth century, or the Ahmadiyya in the Panjab at the turn of the twentieth century, were declared as heresies and, in the case of the Ahmadiyya, as non-Islamic as late as 1974. Hence the merciless persecution in Iran of the Bahais, whose claim to possess a new revelation violated the dogma of Muhammad as the final bearer of Divine revelation.