And now, concerning His words: “And then shall appear the
sign of the Son of man in heaven.” By these words it is meant that when the sun
of the heavenly teachings hath been eclipsed, the stars of the
divinely-established laws have fallen, and the moon of true knowledge—the
educator of mankind—hath been obscured; when the standards of guidance and
felicity have been reversed, and the morn of truth and righteousness hath sunk in
night, then shall the sign of the Son of man appear in heaven. By “heaven” is
meant the visible heaven, inasmuch as when the hour draweth nigh on which the
Day-star of the heaven of justice shall be made manifest, and the Ark of divine
guidance shall sail upon the sea of glory, a star will appear in the heaven,
heralding unto its people the advent of that most great light. In like manner,
in the invisible heaven a star shall be made manifest who, unto the peoples of
the earth, shall act as a harbinger of the break of that true and exalted Morn.
These twofold signs, in the visible and the invisible heaven, have announced
the Revelation of each of the Prophets of God, as is commonly believed.
(Baha'u'llah,
The Kitab-i-Iqan)