ZitatThe one-finger display is the distinctive Muslim gang sign: The index finger points straight up while the thumb wraps underneath and presses against the digital phalange of the middle finger. The remaining fingers are squeezed against the palm in order to highlight the extended forefinger. The extended finger is symbolic of the one-God concept of Muhammad and is understood by all believers to be a symbolic shahada, the Muslim affirmation of faith: There is but one God and Muhammad is his messenger.
Thus when believers stick their index finger in the air, they demonstrate they are partisans of Muhammad’s God concept. And they also affirm their belief in Muhammad’s claim he was the interface between God and man. They also demonstrate they are part of the umma, the exclusive transtribal supertribe of believers that Muhammad started 1,400 years ago.