Circumstance of a Human Act

The circumstance of a human act is one of the three sources needed to determine whether an act is moral or immoral (See object and intention as the other two sources). Circumstances play a role in the morality or immorality of an act by mitigating the evil or enhancing the good.  For example, the circumstance of a married man having relations with someone who is not his wife is more serious than a person who is single committing the same sin. On the other hand, circumstances can render an act more virtuous. For instance,  a poor person giving the little he has to the poor is far more virtuous than a rich person giving from his excess.