To cross one's fingers

 

Keeping one’s fingers crossed is believed to help in making a wish come true.To start with, what is now often merely a figure of speech was a solemn action expecting a twofold result. It would ward off evil forces and attract good luck. This would make certain the fulfillment of a wish. The two crossed fingers symbolized St Andrew’s cross.  A sacred sign, it protected not only the present but as it were, things to come, by keeping away the devil always so eager and ready to destroy hope.

There was magic in the gesture as well which, at the meeting point at the two crossed fingers, ’nailed’  good luck. Thus securely tightly, it could not escaped and thereby ensured that whatever was wanted would happen.