@rstrats,
An idiom is a figure of speech peculiar to people in one place, an expression that means something other than its literal meaning. "Three days and three nights" was a Roman legal requirement: a person was not legally dead until the body had been in the grave for three days and three nights.
The confusion comes from people assuming that "sabbath" meant the usual Saturday sabbath. It did not: it was the passover, which takes precedence over the regular weekly sabbath.
Jesus died about sundown so he rose about sundown. The empty tomb was discovered Sunday morning, so he rose Saturday about sundown. Count back three days and three nights and you find he was crucified on a Wednesday, and the passover was on a Thursday that year.