A number of things are established by Christ’s resurrection.
It proves that God was satisfied with Christ’s offering, since Jesus now sits at His right hand (Romans 8:34). It proves that Jesus is who He said He was: the Son of God (Romans 1:4). It secures our justification (Romans 4:24). It causes us to be born again to a living hope (1 Peter 1:3). It shows His authority as Lord of the living and the dead (Romans 14:9).
And the resurrection guarantees the coming judgment. Paul told this to the Athenians:
The times of ignorance God overlooked, but now He commands all people everywhere to repent, because He has fixed a day on which He will judge the world in righteousness by a man whom He has appointed; and of this He has given assurance to all by raising Him from the dead. (Acts 17:30-31)
When we gather around the Lord’s Table we proclaim the Lord’s death until He comes. We are proclaiming the only way out of judgment, the only way that Christ’s return will be a reason to rejoice, not the day of wrath.
The resurrection establishes Jesus as Lord, the Lord of all believers who rejoice at His name. And the resurrection establishes Jesus as Lord of all, with authority to judge those who currently refuse to acknowledge His name or rebel against Him.
As Christians we do look forward to that “fixed” day. We exalt the appointed and anointed Lord, we are assured of His return. We take refuge in Him, and this comes with the assurance of God’s blessing.