Then certain of the scribes and of the Pharisees answered, saying, Master, we would see a sign from thee. But he answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas: 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.
— Matthew 12:38-40 —
It is three days and three nights. It means exactly what is says. Jesus said that He would only give one sign that would prove that He was who He said He was. His resurrection, after being dead and in the grave for three days and three nights, was the sign. Can you count three days and three nights between "good Friday" sunset until Sunday morning? The most we can count is two nights and one day. If that was the only sign, then Jesus didn't fulfill it in the "Catholic Easter" version. In reality He did fulfill the sign in three literal twenty-four hour days.
The first problem is that the scriptures don't say that Jesus rose on Sunday morning. Jesus didn't resurrect on Sunday morning. He was already gone.
Mark 16:1-6 And when the sabbath was past, Mary Magdalene, and Mary the mother of James, and Salom 2And very early in the morning the first day of the week, they came unto the sepulchre at the rising of the sun. 3And they said among themselves, Who shall roll us away the stone from the door of the sepulchre? 4And when they looked, they saw that the stone was rolled away: for it was very great. 5And entering into the sepulchre, they saw a young man sitting on the right side, clothed in a long white garment; and they were affrighted. 6And he saith unto them, Be not affrighted: Ye seek Jesus of Nazareth, which was crucified: he is risen; he is not here: behold the place where they laid him.
Jesus' body wasn't in the grave on Sunday morning because He had already risen on sabbath evening.
John 18:28 Then led they Jesus from Caiaphas unto the hall of judgment: and it was early; and they themselves went not into the judgment hall, lest they should be defiled; but that they might eat the passover.
John 19:31 The Jews therefore, because it was the preparation, that the bodies should not remain upon the cross on the sabbath day, (for that sabbath day was an high day,) besought Pilate that their legs might be broken, and that they might be taken away.
Luke 23:50-56 And, behold, there was a man named Joseph, a counsellor; and he was a good man, and a just: 51(The same had not consented to the counsel and deed of them;) he was of Arimathaea, a city of the Jews: who also himself waited for the kingdom of God. 52This man went unto Pilate, and begged the body of Jesus. 53And he took it down, and wrapped it in linen, and laid it in a sepulchre that was hewn in stone, wherein never man before was laid. 54And that day was the preparation, and the sabbath drew on. 55And the women also, which came with him from Galilee, followed after, and beheld the sepulchre, and how his body was laid. 56And they returned, and prepared spices and ointments and rested the sabbath day according to the commandment.
That particular sabbath “was an high day.” The Passover is one of seven annual sabbaths. An annual sabbath can fall on any day of the week, so in that week there are two sabbaths.
Jesus was buried just before sunset on the preparation day in order to avoid breaking the annual sabbath, therefore, in order for Him to rise after three days and three nights, He must have risen just before sunset three days later, which was the weekly sabbath. Jesus was buried on the annual sabbath and rose on the weekly sabbath.
If we count backwards three days and three nights from the weekly sabbath at sunset we come to Wednesday sunset. Wednesday evening was the preparation day for the annual sabbath. It was the day when the Passover lambs were killed.

The reason this is so significant is that it tells us in what year Jesus died and rose again. The only year between 30 A.D. and 33 A.D. where the preparation day for the annual sabbath (Passover) fell on a Wednesday was 31 A.D.
There is another piece of information that solidifies the 31 A.D. date. It says John the baptist began to preach "in the fifteenth year of the reign of Tiberius Caesar." History tells us that Tiberius began to reign in September of 14 A.D. His fifteenth year would be 28 A.D., that is when John began to preach. All of the information is already in the Bible. John the baptizer came in 28 A.D. Jesus came to be baptized just prior to Passover 29 A.D. According to the gospel of John, Jesus lived through one more Passover 30 A.D. and was crucified on the third Passover, 31 A.D.
Luke 3:1-4 Now in the fifteenth year of the reign of Tiberius Caesar, Pontius Pilate being governor of Judaea, and Herod being tetrarch of Galilee, and his brother Philip tetrarch of Ituraea and of the region of Trachonitis, and Lysanias the tetrarch of Abilene, 2Annas and Caiaphas being the high priests, the word of God came unto John the son of Zacharias in the wilderness. 3And he came into all the country about Jordan, preaching the baptism of repentance for the remission of sins; 4As it is written in the book of the words of Esaias the prophet, saying, The voice of one crying in the wilderness, Prepare ye the way of the Lord, make his paths straight.
It also tells us when Jesus will return.
Hosea 6:1-3 Come, and let us return unto the LORD: for he hath torn, and he will heal us; he hath smitten, and he will bind us up. 2After two days will he revive us: in the third day he will raise us up, and we shall live in his sight. 3Then shall we know, if we follow on to know the LORD: his going forth is prepared as the morning; and he shall come unto us as the rain, as the latter and former rain unto the earth.
II Peter 3:8 But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day.
The first two verses of Hosea 6 are obviously salvation verses. In verse 1, Jesus reconciles us to God by taking our sins to the cross. In verse 2, He returns to resurrect us and receive His kingdom. The two day (two thousand years) would be from Jesus' crucifixion. If He was crucified in 31 AD, His coming would be two thousand years from then. The "former and latter rain" are Jesus' first and second coming. If two days is two thousand years, Jesus' coming would be two thousand years from His leaving: 2031.
The seven day creation week is the first end time prophecy. God created everything in six days and rested on the seventh. This world was created with an expiration date set in the beginning. There will be six days (6000 yrs.) of man's rule and one day (1000 yrs.) of the Messianic kingdom of God. Until this day the entire world recognizes the seven day week. Every seven day cycle is a perpetual reminder of kingdom come. Remember the sabbath day.
Matthew 6:10 Thy kingdom come. Thy will be done in earth, as it is in heaven.
Isaiah 46:9-10 Remember the former things of old: for I am God, and there is none else; I am God, and there is none like me, 10Declaring the end from the beginning, and from ancient times the things that are not yet done, saying, My counsel shall stand, and I will do all my pleasure:
Matthew 13:37-43 He answered and said unto them, He that soweth the good seed is the Son of man; 38The field is the world; the good seed are the children of the kingdom; but the tares are the children of the wicked one; 39The enemy that sowed them is the devil; the harvest is the end of the world; and the reapers are the angels. 40As therefore the tares are gathered and burned in the fire; so shall it be in the end of this world. 41The Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend, and them which do iniquity; 42And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth. 43Then shall the righteous shine forth as the sun in the kingdom of their Father. Who hath ears to hear, let him hear.
Matthew 24:30 And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.
Revelation 14:14-16 And I looked, and behold a white cloud, and upon the cloud one sat like unto the Son of man, having on his head a golden crown, and in his hand a sharp sickle. 15And another angel came out of the temple, crying with a loud voice to him that sat on the cloud, Thrust in thy sickle, and reap: for the time is come for thee to reap; for the harvest of the earth is ripe. 16And he that sat on the cloud thrust in his sickle on the earth; and the earth was reaped.