To your question/assertion, then...
There is this assertion here; right?
1 Corinthians 15:3 For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; 15:4 And that he was buried, and that he rose again the third day according to the scriptures: 15:5 And that he was seen of Cephas, then of the twelve:
But there is also this one...
Luke 24:19 And he said unto them, What things? And they said unto him, Concerning Jesus of Nazareth, which was a prophet mighty in deed and word before God and all the people: 24:20 And how the chief priests and our rulers delivered him to be condemned to death, and have crucified him. 24:21 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.
24:25 Then he said unto them, O fools, and slow of heart to believe all that the prophets have spoken: 24:26 Ought not Christ to have suffered these things, and to enter into his glory? 24:27 And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself. 24:44 And he said unto them, These are the words which I spake unto you, while I was yet with you, that all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the psalms, concerning me. 24:45 Then opened he their understanding, that they might understand the scriptures, 24:46 And said unto them, Thus it is written, and thus it behoved Christ to suffer, and to rise from the dead the third day:
Obviously, He went over that with them via the Scripture.
Question is, where is this "buried...and rose again the third day" in the OT?
Though I hold that Paul means by is an application DISTINCTLY UNIQUE to that Mystery UNIQUE to his ministry ALONE, at the same time, part of where ISRAEL's Prophesied hope as to that is concerned, in the OT, is asserted in the following...
Acts 2:23 Him, being delivered by the determinate counsel and foreknowledge of God, ye have taken, and by wicked hands have crucified and slain: 2:24 Whom God hath raised up, having loosed the pains of death: because it was not possible that he should be holden of it. 2:25 For David speaketh concerning him, I foresaw the Lord always before my face, for he is on my right hand, that I should not be moved: 2:26 Therefore did my heart rejoice, and my tongue was glad; moreover also my flesh shall rest in hope: 2:27 Because thou wilt not leave my soul in hell, neither wilt thou suffer thine Holy One to see corruption. 2:28 Thou hast made known to me the ways of life; thou shalt make me full of joy with thy countenance. 2:29 Men and brethren, let me freely speak unto you of the patriarch David, that he is both dead and buried, and his sepulchre is with us unto this day. 2:30 Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne; 2:31 He seeing this before spake of the resurrection of Christ, that his soul was not left in hell, neither his flesh did see corruption.
Another part of it is asserted in the following, which is from the OT, also...
Matthew 12:38 Then certain of the scribes and of the Pharisees answered, saying, Master, we would see a sign from thee. 12:39 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: 12:40 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.
And so on...
In short, it is found in a collection of various passages that together paint the intended image of it, and that, THIS SIDE of the Cross.
For, prior to the Cross, it had formed a part of "the mysteries of the kingdom of heaven" (Matt. 13:11) that He had often made reference to in various parables, in types, and figures, and even literally, but that had nevertheless been made prior to the Cross.
Luke 18:31 Then he took unto him the twelve, and said unto them, Behold, we go up to Jerusalem, and all things that are written by the prophets concerning the Son of man shall be accomplished. 18:32 For he shall be delivered unto the Gentiles, and shall be mocked, and spitefully entreated, and spitted on: 18:33 And they shall scourge him, and put him to death: and the third day he shall rise again. 18:34 And they understood none of these things: and this saying was hid from them, neither knew they the things which were spoken.
There was that, PRIOR to the Cross, but also this, AFTER the Cross..
Luke 24:3 And they entered in, and found not the body of the Lord Jesus. 24:4 And it came to pass, as they were much perplexed thereabout, behold, two men stood by them in shining garments: 24:5 And as they were afraid, and bowed down their faces to the earth, they said unto them, Why seek ye the living among the dead? 24:6 He is not here, but is risen: remember how he spake unto you when he was yet in Galilee, 24:7 Saying, The Son of man must be delivered into the hands of sinful men, and be crucified, and the third day rise again. 24:8 And they remembered his words, 24:9 And returned from the sepulchre, and told all these things unto the eleven, and to all the rest.
Likewise had been the case with the Prophets themselves...
1 Peter 1:3 Blessed be the God and Father of our Lord Jesus Christ, which according to his abundant mercy hath begotten us again unto a lively hope by the resurrection of Jesus Christ from the dead, 1:4 To an inheritance incorruptible, and undefiled, and that fadeth not away, reserved in heaven for you, 1:5 Who are kept by the power of God through faith unto salvation ready to be revealed in the last time.
1:9 Receiving the end of your faith, even the salvation of your souls. 1:10 Of which salvation the prophets have enquired and searched diligently, who prophesied of the grace that should come unto you: 1:11 Searching what, or what manner of time the Spirit of Christ which was in them did signify, when it testified beforehand the sufferings of Christ, and the glory that should follow. 1:12 Unto whom it was revealed, that not unto themselves, but unto us they did minister the things, which are now reported unto you by them that have preached the gospel unto you with the Holy Ghost sent down from heaven; which things the angels desire to look into. 1:13 Wherefore gird up the loins of your mind, be sober, and hope to the end for the grace that is to be brought unto you at the revelation of Jesus Christ;
Right there you have it also, and also the teaching of His Prophesied return one day - which is another issue in connection with God's plan and purpose for a redeemed Israel unto His planned service election for them one day over this Earth, in that day of their adoption (Bar Mitzvah) at last, that does not right off appear to depict Two separate Advents in the OT, though there all along those Two separate Advents of His turn out to have been written of, all along.
Rom. 5:6-8 towards you.