It’s going to be BIBLICAL!
Why is Friday the 13th Unlucky?
According to BIBLICAL l tradition, 13 guests attended the Last Supper, held on Maundy Thursday, including Jesus and his 12 apostles (one of whom, Judas, betrayed him). The next day, of course, was Good Friday, the day of Jesus’ crucifixion.
The seating arrangement at the Last Supper is believed to have given rise to a longstanding Christian superstition that having 13 guests at a table was a bad omen—specifically, that it was courting death.
https://www.history.com/topics/folklore/friday-the-13th