Sin inherited from Adam and Eve, the first humans created by God, who broke the perfect relationship between God and humans by disobeying God's command
Sins that are the consequences of a person's actions, for example shoplifting would be considered a sin because it goes against a direct commandment from God not to steal
Many Christians believe that people who die with unforgiven sins will not go to Heaven, and may go to Hell. Catholics believe these people may be sent to Purgatory
For Catholics, this might mean receiving the sacraments, such as being baptised or getting married. For Protestants, this might mean a personal acceptance of Jesus as the Lord and Saviour
The ideas of salvation and atonement are very closely linked in Christianity. Atonement is the idea of the relationship between humans and God being healed, with God and humanity becoming united