What would have changed if Jesus had not risen from the dead?
Not much.
We would still be dead in our sins (see 1 Corinthians 15:17).
We would lie still forever in the grave. There would be no resurrection for us (see 1 Corinthians 15:12-58).
The universe would inevitably burn up and fizzle out, just like many expect, since Jesus would not be the firstborn of all creation, the firstborn from the dead, and the one through whom God would reconcile all things on earth and heaven (contra Colossians 1:15-20). Until everything decays and wastes away, the creation would simply groan with no expectant hope (contra Romans 8:22).
Jesus’ disciples would have stayed locked up in fear behind closed doors (John 20:19-23).
Fertility cults involving resurrection myths would still remain, but with no alternative Christian truth claim declaring what C. S. Lewis realized: Jesus is the myth that became fact (See C. S. Lewis, Surprised by Joy: The Shape of My Early Life {London: Geoffrey Bles, 1955}, 222).
Easter Bunny-like festivities would still arise time and time again. So at least we would have something to look forward to!
Jesus would have been the weak, pitiful, blaspheming idiot his enemies and naysayers took him to be (Matthew 27:27-44; see also 1 Corinthians 1:18-31). In that case, the gospel of might and the price is always right for the rich, wise and powerful would have continued to proceed unimpeded, trampling underfoot the widow, orphan and alien with whom Jesus identified.
But many things have changed given that God raised Jesus from the dead.
We are no longer dead in our sins.
We will rise bodily from the dead.
The creation does indeed groan awaiting our redemption.
The church broke out in courageous love on Pentecost, as the Spirit of the resurrected Jesus was poured out (see Acts 2). In view of Jesus’ resurrection, may the church today not cower in fear, but be poured out in love as the Spirit of Jesus falls on us again and again.
The resurrection is God’s rebuke of Jesus’ enemies and naysayers, as he secures the weak, the simple and poor in his resurrecting love. Jesus is no loser, liar, or lunatic. Nor are those who trust in him. As Jesus said to Martha, so he says to each of us, “I am the resurrection and the life. Whoever believes in me, though he die, yet shall he live, and everyone who lives and believes in me shall never die. Do you believe this?” (John 11:25-26; ESV)
Jesus is risen! He is risen indeed!