Eternal sin
Thomas Aquinas lists, or has responded to, six sins that supposedly go against the Holy Spirit:
Thomas Aquinas explains that the unforgivability of blasphemy against the Holy Spirit means that it removes the entrance to these means of salvation; however, it cannot hinder God in taking away this obstacle by way of a miracle.
Ten Commandments
The Ten Commandments concern matters of fundamental importance in Judaism and Christianity: the greatest obligation (to worship only God), the greatest injury to a person (murder), the greatest injury to family bonds (adultery), the greatest injury to commerce and law (bearing false witness), the greatest inter-generational obligation (honour to parents), the greatest obligation to community (truthfulness), the greatest injury to moveable property (theft).