I don't recall the expression "exact sign" appearing in Scripture, plus it is impossible for Jesus to be in the tomb for "3 days and 3 nights" AND rise on the third day, which Jesus said He would. So you make Jesus out to be a list. The testimony of the disciples on the road to Emmaus proves that He did in fact rise "on the third day" so it demonstrates that you misunderstand what He meant by "3 days and 3 nights".
3 days and 3 nights seems very exact to me.
Died wed afternoon
In grave wed night
thursday day and night
fri day and night
Resurrected Sat day evening
1 st day wed evening to thurs evening
2nd day thurs evening to fri evening
3rd day fri evening to Sat evening
Road to Emmaus event.
You mean this verse which was badly translated?
KJV 21 But we trusted that it had been he which should have redeemed Israel: and beside all this, to day is the third day since these things were done.
The word badly translated is 'since'.
apo: from, away from
Original Word: ἀπό
Part of Speech: Preposition
Transliteration: apo
Phonetic Spelling: (apo')
Definition: from, away from
Usage: from, away from.
Other translations
Moffatt Translation–by James Moffatt “….but he is dead, and that is three days ago!”
The Bible in Basic English Version says, “In addition to all this he has now let three days go by from the time when these things took place;”
James Murdock Translation has it, “And lo, three days [have passed], since all these things occurred.”
The New Berkeley Version in Modern English– Gerrit Verkugl “Moreover, three days have already passed, since all these events occurred.”
The Syriac New Testament Translated Into English From The Peshitto Version — James Murdock “…and lo, three days have passed since all these things have occurred.”
Youngs Literal and we were hoping that he it is who is about to redeem Israel, and also with all these things, this third day is passing to-day, since these things happened.
It is quite evident that it is past the third day of the resurrection, probably best translated as
"today is after the third day since these things were done"