thisnumbersdisconnected,
re: "...the Jews considered part of a day a whole day."
As regards the Jewish practice of counting any part of a day as a whole day I would agree, but when "nights" is added to "days" to yield a phrase such as 3 days AND 3 nights, it normally refers to a consecutive time period where "day" refers to the light portion of a 24 hour period and "night" refers to the dark portion of a 24 hour period. No one In the history of apologetics as far as I know has ever presented any historical documentation that a phrase such as 3 days AND 3 nights was a unique first century idiom of Hebrew/Aramaic/Greek which could mean something different than what the phrase means in English. If you have such documentation that shows that a phrase stating a certain number of days, as well as a certain number of nights was ever used in the first century or before when it absolutely didn’t/couldn't include at least parts of the specified number of days and at least parts of the specified number of nights, I would very much like to see it.
BTW, Luke 24:21 indicates that the crucifixion could not have taken place any later than the 5th day of the week.
As Rhett said to Scarlet, "Frankly, my dear..." I really don't think it matters what some commentator said about how the Jews might have counted days and nights, what I do care about is how Christ counted it. He was the one who was going to be interrred for three days and three nights and He is the final authority. What does He say about day and night?
Joh 11:9 Jesus answered,
Are there not twelve hours in the day? If any man walk in the day, he stumbleth not, because he seeth the light of this world.
Joh 11:10 But if a man walk in the night, he stumbleth, because there is no light in him.
How many hours are there in the day? There are twelve. How many hours are there left for night? Twelve. Christ, Himself, does not count partial time as a full daylight period. He calls it twelve hours. Christ was the Creator of days, what constitutes a day?
Gen 1:5 And God called the light Day, and the darkness he called Night.
And the evening and the morning were the first day.
Gen 1:8 And God called the firmament Heaven.
And the evening and the morning were the second day.
Gen 1:13
And the evening and the morning were the third day.
Gen 1:19
And the evening and the morning were the fourth day.
Gen 1:23
And the evening and the morning were the fifth day.
Gen 1:31 And God saw every thing that he had made, and, behold, it was very good.
And the evening and the morning were the sixth day.
Now, how long are the Sabbath days?
Lev 23:32 It shall be unto you a sabbath of rest, and ye shall afflict your souls: in the ninth day of the month at even,
from even unto even, shall ye celebrate your sabbath.
How does the Maker of days and nights, the Creator of time and the calendar reckon a day? From evening to evening, sunset to sunset is a day.
A good read here is some research on the Quarto-Decimani controversy. Easter and Sunday were not the days of the early church, they kept the Passover and the Sabbath.