Christianity and Judaism
In contrast to the Jewish view of being morally balanced, Original Sin refers to the idea that the sin of Adam and Eve's disobedience (sin "at the origin") has passed on a spiritual heritage, so to speak. Christians teach that human beings inherit a corrupted or damaged human nature in which the tendency to do bad is greater than it would have been otherwise, so much so that human nature would not be capable now of participating in the afterlife with God. This is not a matter of being "guilty" of anything; each person is only personally guilty of their own actual sins. However, this understanding of original sin is what lies behind the Christian emphasis on the need for spiritual salvation from a spiritual Saviour, who can forgive and set aside sin even though humans are not inherently pure and worthy of such salvation. Paul the Apostle in Romans and I Corinthians placed special emphasis on this doctrine, and stressed that belief in Jesus would allow Christians to overcome death and attain salvation in the hereafter.
Internal sin
Internal sin, in Christianity, is the idea that sin may be committed not only by outward deeds but also by the inner activity of the mind, quite apart from any external manifestation. Thought crimes were as old as heresy, but the Reformation's alarms received new emphasis at the Council of Trent (Session XIV, chapter. v). The session, while reiterating that all mortal sins must be confessed, singled out the unspoken ones that "sometimes more grievously wound the soul and are more dangerous than sins which are openly committed".