keep one's fingers crossed, to

keep one's fingers crossed (for someone or something)

 and cross one's fingers
to wish for luck for someone or something, sometimes by actually crossing one's fingers; to hope for a good outcome for someone or something. I hope you win the race Saturday. I'm keeping my fingers crossed for you. I'm trying out for a play. Keep your fingers crossed!
See also: crosse, finger, keep

keep one's fingers crossed, to

To hope for success. This saying comes from an ancient superstition that making the sign of the cross will avert bad luck. Often put as Keep your fingers crossed, meaning “Wish me luck,” it dates from the 1920s. One writer points out it may also have come from children’s games in which crossing one’s fingers denotes that one is “safe,” as well as the gambit of telling a lie with one’s fingers crossed, presumably to avoid punishment for this sinful act.
See also: finger, keep