The ancient Jewish people believed that God would restore us to our original design and relationship with God, one another, and Creation. This New Creation would be signified by the resurrection of the dead, an experience they believed would happen once, at the end of time. They never expected one man to be resurrected in the middle of time.
Jesus’ resurrection has inaugurated God’s New Creation. We live in the time between times—after Christ’s resurrection, which signifies New Creation has begun, and in anticipation of the time when New Creation will be completely realized. As such, the resurrection means God’s Kingdom is already here, but not yet fully realized. This already-not-yet tension is the reason we sometimes see God move in miraculous ways, and in other times are disappointed; why we sometimes experience moments of remarkable charity and brotherly love, and at other times are victims of cruelty and suffering.
We can experience foreshocks of the Kingdom, but it has not totally manifested.
Adapted from Why God Died