The first thing that stuck in the minds of the disciples was not the empty tomb, but rather the empty grave clothes - undisturbed in form and position.
Paul the apostle recounted that Jesus appeared to more than 500 of His followers at one time, the majority of whom were still alive and who could confirm what Paul wrote.
On that Sunday morning the first thing that impressed the people who approached the tomb was the unusual position of the one and a half to two ton stone that had been lodged in front of the doorway.
Jesus claimed He had the power to raise himself from the dead and His followers would be raised from the dead. That's a unique claim in the literature of religion.
If Jesus Christ was who He claimed to be, and He did die on a cross at a point of time in history, then, for all history past and all history future it is relevant because that is the very focal point for forgiveness and redemption.
Here's the simplest answer: Within weeks, the disciples proclaimed the resurrection of Jesus Christ, that He had been bodily raised from the dead and appeared to them.
