Why do some people say "13" is an unknown number?

From Norwegian mythology, people have an idea that it is unlucky for 13 people to sit together and eat. This superstition was confirmed by the last supper of Jesus and his 12 disciples. The Bible says that at the last supper, Jesus sat with his 65,438+02 disciples, which was exactly 65,438+03. Judas, one of his disciples, sold his teacher for thirty silver coins.