Mark 9:12- And he answered and told them, Elias verily cometh first, and restoreth all things; and how it is written of the Son of man, that he must suffer many things, and be set at nought.
Luke 9:22-Saying, The Son of man must suffer many things, and be rejected of the elders and chief priests and scribes, and be slain, and be raised the third day.
Luke 17:25 Jesus says, "But first must he suffer many things, and be rejected of this generation. "
When Peter denied that Jesus was going to die and suffer many things, then rise again, Jesus rebuked him and said, "Get thee behind me, Satan: thou art an offence unto me: for thou savourest not the things that be of God, but those that be of men." (Matthew 16:24, Mark 8:33).
So according to Jesus, if you deny His death on the cross, and His ressurection, you are like Satan. Jesus even called His own desciple Satan. So just think what He will do to those who are not His desciples that deny His death. When someone denies that Jesus died for their sins and rely on their works for salvation, that is of men and not of God, as Jesus puts it. You can't make your own way to Paradise, God makes the way.