If Christ be not risen our preaching is vain, and our faith is imaginary or meaningless. We are still in our sins.
Those who have died in Christ are lost, they have perished. If Christ has not risen from the dead we are to be pitied, and of all people we are the most miserable. In other words the fabric of our faith lies in shambles around us.
But Paul continues on the positive side. “But now is Christ risen from the dead, and has become the first fruits of them that sleep in Jesus.”
Christ appeared ten times during the days of manifestation, before His ascension. He also appeared to three men one or more times after His ascension.
(1) To Stephen at his stoning - Acts 7:55-60.
(2) To Paul at his conversion - Acts 9:3-8.
at Corinth - Acts 18:9-10.
in the temple at Jerusalem - Acts 22:17-21.
later at Jerusalem - Acts 23:11.
in another vision - 2 Corinthians 12:1-4.
(3) To John on Patmos - Revelations 1:10-19.
He appeared also in other visions in The Revelation.