1 Cor 15:3-4
It was prophesied in the Old Testament that God would raise Christ from the dead. God raised Jesus from the dead. That is, Jesus is the Christ who came as prophesied in the Old Testament.
Acts 13:29 And when they had fulfilled all that was written of him, they took him down from the tree, and laid him in a sepulchre. 30 But God raised him from the dead: 31 And he was seen many days of them which came up with him from Galilee to Jerusalem, who are his witnesses unto the people. 32 And we declare unto you glad tidings, how that the promise which was made unto the fathers, 33 God hath fulfilled the same unto us their children, in that he hath raised up Jesus again; as it is also written in the second psalm, Thou art my Son, this day have I begotten thee. 34 And as concerning that he raised him up from the dead, now no more to return to corruption, he said on this wise, I will give you the sure mercies of David. 35 Wherefore he saith also in another psalm, Thou shalt not suffer thine Holy One to see corruption. 36 For David, after he had served his own generation by the will of God, fell on sleep, and was laid unto his fathers, and saw corruption: 37 But he, whom God raised again, saw no corruption.
1 Cor 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; 4 And that he was buried, and that he rose again the third day according to the scriptures: