For Christ also suffered once for sins, the righteous for the unrighteous, that he might bring us to God,
being put to death in the flesh but made alive in the spirit,...
through the resurrection of Jesus Christ, who has gone into heaven and is at the right hand of God, with angels, authorities, and powers having been subjected to him.

The wages of sin is death: Jesus Christ has died, to reconcile the sinner to God, and he who died (was righteous or just) rose again, now having the power to deal with Satan. He also will judge all; and those not reconciled to him will be enternally separated from God, in hell. Thus the simple message of the gospel is believe in Jesus Christ, knowing that judgement is coming.