The Big Quake

The world is in travail, and its agitation waxeth day by day. Its face is turned towards waywardness and unbelief. Such shall be its plight, that to disclose it now would not be meet and seemly. Its perversity will long continue. And when the appointed hour is come, there shall suddenly appear that which shall cause the limbs of mankind to quake. Then, and only then, will the Divine Standard be unfurled, and the Nightingale of Paradise warble its melody. - Gleanings from the Writings of Bahá'u'lláh

So said Bahá'u'lláh, well over a century ago. To his credit, he was not foretelling anything in the immediate future; rather he spoke of a more distant future. He speaks of two events which shall come concurrently:

1) there shall suddenly appear that which shall cause the limbs of mankind to quake.

2) the Divine Standard [will] be unfurled, and the Nightingale of Paradise warble its melody.

What does he mean by limbs quaking? It happens that he speaks of limbs quaking in several contexts:

• "Certain wrong-doers who profess allegiance to the Cause of God committed such deeds as have caused the limbs of sincerity, of honesty, of justice, of equity to quake." - KALêMçT-I-FIRDAWSêYYIH
• "... His Great Revelation which hath caused the limbs of all mankind to quake ..." - ISHRçQçT
• "... this Name which hath caused all other names to groan aloud and the limbs of the sages to quake ..." - ISHRçQçT
• "... the She-Serpent [The Imám-Jum'ih of Isfahán, see page 203.] whose cruelty hath caused all created things to groan, and the limbs of the holy ones to quake." -Epistle to the Son of the Wolf
• "This is the Word which hath caused the limbs of disbelievers to quake." - Tablets of Bahá'u'lláh revealed after the Kitáb-i-Aqdas
• "... confessed their belief in that which hath made the limbs of the oppressors among Thy creatures to quake,... " - Gleanings from the Writings of Bahá'u'lláh
• " This is the Announcement that hath caused the limbs of mankind to quake , except such as God, the Protector, the Helper, the Succorer, hath willed to exempt. Men have indeed with their own eyes witnessed how all men and all things have been thrown into confusion and been sore perplexed, save those whom God hath chosen to exempt." -Epistle to the Son of the Wolf

Clearly, the image of limbs quaking was used by Bahá'u'lláh to depict agitation, confusion, or a similar emotion. A literal interpretation, such as nerve gas or mass hysteria, is not justifiable. This is not a prophecy of specify events or phenomena, but merely a statement that things will get worse before they get better.

Or, maybe it was a retroactive prophecy of Mormon prophet Joseph Smith, who spoke thus of the voice of God: the still small voice, which whispereth through and pierceth all things, and oftentimes it maketh my bones to quake while it maketh manifest (D&C 85).

Or ... maybe it's just a common way of expressing excitement, rapture, agitation, and who knows what else?