What is the origin of the phrase"keep your fingers crossed''?

One answer I found online: I've read that it's literally making the sign of the cross to ask for God's help. Interestingly, you can also cross your fingers behind your back to cover up a lie, and this supposedly comes from religious persecution; when people were asked if they were Christians, they would lie and say no to escape Roman retribution, but make the sign of the cross behind their back to ask God's forgiveness for the lie.

Another answer I found online: KEEP YOUR FINGERS CROSSED -- From "Random House Dictionary of Popular Proverbs and Sayings" by Gregory Y. Titelman: "Hope for success. The saying derives from the superstition that bad luck may be averted by making the sign of the cross.

Another response: But when things aren’t going “OK” and you just need some plain luck, what do you do? You cross your fingers, of course. Or some may ask you to “keep your fingers crossed” for them before they scratch that lottery ticket. This gesture originates from the custom of making a wish upon the cross. It was believed that the cross was a symbol of unity and that benign spirits dwelt at its intersecting point -- to wish on a cross was a figurative way of securing the wish at the intersection until it came true. This custom dates back to pre-Christian times and, in many early European cultures, two people were required to use their index fingers to form the sign, one to make the wish and the other to support it. Over the years, the custom was modified so one person could make a wish on his/her own.

So if you cross your fingers for, say, your favorite sports team to win and they make a last minute goal, touchdown, basket or whatever, you might exclaim, “Boy, that was in the nick of time!” And sport is exactly where that expression came from. Many centuries ago, points in a game -similar to today’s soccer -- were notched into wooden sticks called tallies. When a last minute score brought victory, it was called the “nick in time