It's bad luck to walk under a ladder. This came from the early Christian belief that a leaning ladder formed a triangle with the wall and ground. You must never violate the Holy Trinity by walking through a triangle, lest you be considered in league with the devil. (And you all know what good Christians did to people they suspected of being in league with the devil.)
Beware of Friday the Thirteenth. Those who know about these things, inform us that Adam and Eve were expelled from the Garden of Eden on a Friday, Noah's flood started on a Friday, and Christ was crucified on a Friday. Christians also noted that twelve witches plus one devil are present at Satanic ceremonies so Friday and 13 make a deadly combination.
God Bless You. During the sixth century, it was customary to congratulate people who sneezed because they were expelling evil from their bodies. Later, when a great plague took hold of Europe, and people began sneezing violently, the Pope passed a law. Since sneezing meant that the person was going to die of plague, people were required to bless the sneezer.
Don't spill the salt. Although some people believe that Judas spilt salt during the last supper, this claim can't be proven. Salt was a very precious expensive commodity in the middle ages. It was also used for medicinal purposes. If you spilled any, you must immediately throw it over your left shoulder to strike the nasty spirits in the eye, thus preventing sickness.
Wear a St. Christopher Medal when you travel. Historians don't believe there ever was a Saint Christopher.
Black cats are evil. In ancient Egypt, the Goddess Bast, was a black female cat. Christian priests wanted to wipe out all traces of other religions so convinced their ignorant followers to destroy the evil demons that were black cats. While they were at it, they destroyed the kindly little old ladies who cared for the cats believing them to be witches.
Ladybird, ladybird, fly away home. It is bad luck to kill a ladybug because it represents the Virgin Mary.
Pie In The Sky. Of course, this means to search for the impossible dream but it originated in the early 1900's. A famous labor organizer named Joe Hill was extremely critical of the clergy's treatment of slaves. He wrote a tune called 'The Preacher and the Slave" accusing the clergy of making false promises of a better life in heaven while people starved on earth. The song goes: 'Work and pray, live on hay. You'll get pie in the sky when you die. That's a lie!'
Skin Of Your Teeth. This saying means to barely escape from a harrowing situation. It comes from Job 19:20, where God inflicts all sorts of terrible things on one of those who love him. Poor Job had all his animals stolen, his children die, his house collapse and his body covered with sores. Job has this to say; "My bone cleaveth to my skin and to my flesh, and I am escaped with the skin of my teeth."
Fleshpot. - Today 'fleshpot' describes decadence. In the time of Moses, it was a large pot in which to boil meat. Somehow, preachers managed to change the meaning to scare their flock about 'sins of the flesh'.
To make a scapegoat. - The poor scapegoat gets the punishment for everyone else's mistakes. God condoned this cruelty to animals in Leviticus 16:7-10 "And Aaron shall cast lots upon the two goats; one lot for the Lord, and the other for the scapegoat." The scapegoat got to escape, and carry the tribe's sins into the wilderness, to be eaten by some animal instead of being offered alive as a sacrifice for the Lord.
Christmas and the Star of Bethlehem. - There is no historical evidence that Christ was born on December 25th. December 25th was officially adopted by Bishop Liberius of Rome in 354. December 25th occurs during the rainy season in the Holy Land, so it is highly unlikely that shepherds would be outside in their pastures. The Hayden Planetarium in New York recreated the heavens as they were in the time that Christ was allegedly born. Although nothing spectacular happened in the skies on the date of Christ's birth, the Planetarium went back to the year 6 B.C. On that date, there were three stars in close proximity which created a spectacularly bright beacon, which may account for the stories of the Star of Bethlehem. The most plausible reason that December 25 was chosen as a day to celebrate Christ's birth was that the Christian fathers were trying to compete with another growing religion, Mithraism - the worship of a sun god - whose holy day was also December 25.
Easter - The name "Easter' derives from Eostre, the Anglo-Saxon dawn goddess. She was traditionally honored at the beginning of spring. Easter wasn't celebrated in North America until after the Civil War when religious leaders decided that the country needed a holiday which stressed rebirth.
Religion is a superstition, but is seldom classified as such because it is so widely accepted. Without superstition, religion wouldn't exist, and God wouldn't even have been a concept. Religion equals an extreme case of irrationality.