Was Jesus crucified on Friday or Thursday?
The direct chronological statements converge on Friday: Mark 15:42 identifies the burial day as paraskeue (preparation day = Friday), Luke 24:21 counts Sunday as the third day since the crucifixion (which points back to Friday), and 1 Corinthians 15:4 says he was raised 'on the third day' — not 'after three days.'
The direct statements in the Gospels point to Friday, and three of them are precise enough to count on.
Mark 15:42 tells us the burial happened on paraskeue (παρασκευή, G3904) — which Mark explains for his Gentile readers as "the day before the Sabbath." By the first century, paraskeue had become the standard Greek name for Friday, which it still is in Modern Greek. Luke 24:21 is even more specific: on Sunday morning, the Emmaus disciples say "today is the third day since these things happened." Count back with the inclusive reckoning everyone used: Sunday is day three, Saturday is day two, Friday is day one. If Thursday were the crucifixion day, they would have said "today is the fourth day." Paul clinches the language in 1 Corinthians 15:4: Jesus was raised "on the third day" (te hemera te trite, not "after three days"). Friday to Sunday, counted inclusively, is three days.
The Thursday position starts from John 19:31, which calls the Sabbath following the crucifixion "great" (megale, G3173) — an adjective that appears nowhere else in the New Testament applied to a Sabbath. The Thursday argument: the "great" day was the festival Sabbath of Nisan 15 (the first day of Unleavened Bread, a holy convocation per Leviticus 23:7) falling on Friday, with the regular weekly Sabbath on Saturday. This creates a gap day between the two Sabbaths for the women to buy spices (Mark 16:1), which they couldn't do on Nisan 15.
The Friday response: if Nisan 15 and the weekly Sabbath fell on the same Saturday, a Sabbath carrying both sanctities would naturally earn the adjective "great." Astronomical reconstruction shows that in both AD 30 and AD 33, Nisan 14 fell on a Friday — putting Nisan 15 and the weekly Sabbath on the same Saturday.
There's one more detail worth noting. Paul calls the resurrection "the firstfruits" (1 Cor 15:20). Leviticus 23:11 places the firstfruits offering on "the day after the Sabbath" — which under Pharisaic reckoning (the reckoning that governed temple practice) fell on Nisan 16. A Friday crucifixion puts Sunday as Nisan 16. The calendrical alignment is exact. For the full analysis, see Three Days and Three Nights.
Does 'three days and three nights' in Matthew 12:40 require a Thursday crucifixion?
No. The phrase is a quotation from Jonah 1:17, and the book of Esther shows the same Hebrew idiom operating with inclusive counting — 'three days, night and day' resolved by 'on the third day' (Esther 4:16, 5:1) — which fits a Friday crucifixion without any contradiction.
What does the 'great' sabbath in John 19:31 mean?
John calls the Sabbath following the crucifixion 'great' (megale, G3173) — a term unique in the NT for a Sabbath. The most textually grounded explanation is that Nisan 15 (the festival Sabbath of Leviticus 23:7) coincided with the weekly Sabbath on the same day, giving it double sanctity.