Let us set the record straight. I did NOT write Matthew 12:40 and the WORDS recorded say the following.
For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth.
This is Christ speaking, not me, and there is NO need for anyone to interpret what is said. IT is a declaration, plain and simple.
Matthew 20:19 does NOT change the three days and three nights as was Jonah in the whale's belly. Day three would be on Saturday right up until the clock struck the instant of the sun setting. The NEW day (first day of the week) began AT sun set.
And given the night after the cruifixation was a 'holy' day the burial staff would have done everything they could to have Him entombed BEFORE the 'sun set'.
So the sun sets and then sets again on Thursday. One day. Then it sets on Friday. Two days. Then it sets on Saturday. Three days "in the heart of the earth." Then, after the sun sets on Saturday - in other words, on the fourth day - He rises.
We are left with the same problem: everywhere else in Scripture He rises on the third day, not the fourth.
Starting the timeline on Wednesday does not resolve that difficulty. If He is "in the heart of the earth" for three entire chronological days, He does not rise on the third day - He is "in the heart of the earth" that entire day.