Jonah 1:
17 And the Lord appointed a great fish to swallow up Jonah. And Jonah was in the belly of the fish three days and three nights.
The Hebrew idiom "three days and three nights" does not mean 3 24-hours days.
Gill's Exposition:
and Jonah was in the belly of the fish three days and three nights: that is, one whole natural day, consisting of twenty four hours, and part of two others;
Jesus cited Jonah in Matthew 12:
40 For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth.
That was the only place in the NT where Jesus mentioned
three days and three nights and it was in connection with Jonah's Hebrew idiom.
Elsewhere in Mark, Jesus talked about "after three days", Mark 8:
31 And he began to teach them that the Son of Man must suffer many things and be rejected by the elders and the chief priests and the scribes and be killed, and after three days rise again.
Mark 9:
31 For he was teaching his disciples, saying to them, “The Son of Man is going to be delivered into the hands of men, and they will kill him. And when he is killed, after three days he will rise.”
Mark 10:
34 And they will mock him and spit on him, and flog him and kill him. And after three days he will rise.
Other listeners understood that as "in three days", Mark 14:
58 “We heard him say, ‘I will destroy this temple that is made with hands, and in three days I will build another, not made with hands.’”
More precisely, Jesus frequently talked about "on the third day", Luke 9:
22 Saying, “The Son of Man must suffer many things and be rejected by the elders and chief priests and scribes, and be killed, and on the third day be raised.”
Luke 24:
7 That the Son of Man must be delivered into the hands of sinful men and be crucified and on the third day rise.” 46 And said to them, “Thus it is written, that the Christ should suffer and *on the third day rise from the dead,
Matthew 16:
21 From that time Jesus began to show his disciples that he must go to Jerusalem and suffer many things from the elders and chief priests and scribes, and be killed, and on the third day be raised.
Matthew 17:
23 And they will kill him, and he will be raised on the third day.” And they were greatly distressed.
Matthew 20:
19 And deliver him over to the Gentiles to be mocked and flogged and crucified, and he will be raised on the third day.”
That's what the Jews understood, Matthew 27:
63 And said, “Sir, we remember how that impostor said, while he was still alive, ‘After three days I will rise.’ 64 Therefore order the tomb to be made secure until the third day, lest his disciples go and steal him away and tell the people, ‘He has risen from the dead,’ and the last fraud will be worse than the first.”
In fact, on the day of resurrection, Jesus met two disciples on the road to Emmaus, Luke 24:
21 But we had hoped that he was the one to redeem Israel. Yes, and besides all this, it is now the third day since these things happened.
That confirmed that Jesus rose on the 3rd day. There are other confirmations,
Acts 10:
40 But God raised him on the third day and made him to appear,
1 Corinthians 15:
4 that he was buried, that he was raised on the third day according to the Scriptures,
"3 days and 3 nights" was an ancient Hebrew idiom; in fact and precision, Jesus rose on the 3rd day.
