Eternal sin
In Christian hamartiology, eternal sins, unforgivable sins, or unpardonable sins are sins which will not be forgiven by God. One eternal or unforgivable sin (blasphemy against the Holy Spirit) is specified in several passages of the Synoptic Gospels, including , , and .
Seven deadly sins
With Christianity, historic Christian denominations such as the Catholic Church and Protestant Churches, including the Lutheran Church, recognize seven virtues, which correspond inversely to each of the seven deadly sins. 
Confession is the act of admitting the commission of a sin to a priest, who in turn will forgive the person in the name (in the person) of Christ, give a penance to (partially) make up for the offense, and advise the person on what he or she should do afterwards.