Paul is writing, reminding us how believers, believe in the literal resurrection of Christ. If you don't believe in the resurrection of Christ, you are not a believer in Christ! If Christ had not been raised, then your faith is worthless and your still in sin. If Christ had not been raised, then your preaching is in vain, and your faith is also in vain. God is the God of love and is also a God of justice. While he loves us with a love that is greater than human love, he also jusges sin and evil with prefect justice.