Part VI. The Sixth and Ninth Commandments

It is usual to treat of these two Commandments together, for the Sixth, “Thou shalt not commit adultery,”¹ in expressly forbidding the chief sin, implicitly forbids all other external sins against the laws of marriage, and the Ninth, “Thou shalt not covet thy neighbour’s house, neither shalt thou desire his wife,’’² forbids internal sins of covetousness and lust. The general doctrine concerning internal sins was given in a former Book; the special doctrine about covetousness in so far as it is against justice is clear from what was said about avarice and what will be said later about justice; the doctrine about external sins of lust will be evident from what has to be said in this place.

¹ Exod. xx 14.

² Exod. xx 17.