Prophesied in the Old Testament, but it was prophesied, as well, in a sense, in the new, in John chapter 2 verse 19. "Jesus said this, 'Destroy this temple, and in three days I will raise it up.'"Jesus as prophet
The resurrection of Christ from the dead was a declaration of the Sonship of Christ.
Primarily what the resurrection proved was THE COMPLETION of the work of Christ and stamps "it is finished " with an exclamation point..1 Cor .."If Christ is not risen, then our faith is in vain. We are yet in our sins, and we are of all men most miserable."
So on Easter Sunday..we do not celebrate an incomplete salvation ...but a complete one
And yet, the Catholic church still has Him being sacrificed, but never victorious. Constantly dying and being killed, but never rising and conquering.
We OTOH, worship THIS Christ, the risen and glorified Christ.
Revelation 1:12-16 Then I turned to see the voice that was speaking to me, and on turning I saw seven golden lampstands, and in the midst of the lampstands one like a son of man, clothed with a long robe and with a golden sash around his chest.
The hairs of his head were white, like white wool, like snow. His eyes were like a flame of fire, his feet were like burnished bronze, refined in a furnace, and his voice was like the roar of many waters. In his right hand he held seven stars, from his mouth came a sharp two-edged sword, and his face was like the sun shining in full strength.