cross one's fingers

The story

* As a gesture of good luck, from the Christian notion of inconspicuously making a sign of the cross as an invocation to God. * As a gesture of lying, probably from the Schwurhand, a gesture used in some European countries when taking an oath. The right hand is raised with the index and middle fingers extended upwards (somewhat similarly to a V sign but with the thumb on the side). By crossing the two fingers, the oath is thus symbolically broken.