First: the number 13 are traditionally 'jinxed' (13 at the table) possibly derived from "the last supper" a sad occasion. Second: "Good Friday" is the day of the crucifiction, another sad occasion even if it helped the faithful.
Jesus was crucified on a Wednesday. He was put in the grave about sundown, stayed there three days and three nights, and rose about sundown Saturday evening. The empty grave was discovered Sunday morning.
JakobA the unAmerican. 