Sin has entered the world through Adam's disobedience, now sin has passed through to every person being born into the world. This means we are unholy, sinful, deserving of death and hellfire. Jesus Christ, God's Son, was sent by God the Father to die on the cross for our sins taking the punishment of death we all deserve. If we acknowledge our sin and confess it to God in Jesus Name, if we believe He died on the cross for our sins and rose again (ascending into Heaven) and that He is the Son of God, to whom we must submit our whole life to, then we will be saved. Salvation is a free gift of God (Grace) that comes through faith in Jesus, not by good works we do (being a "good" person won't save you from hell). Works will come as a result of a Godly lifestyle after the free gift of salvation.