What Comes in Groups of Seven?
Things that come in groups of seven include the days of the week, the cervical vertebrae of most mammals and the seven deadly sins. The number is frequently used for groups in religious contexts, such as in the number of levels of heaven in Islam.
In the New Testament, the seven deadly sins are complemented by the seven virtues, which are humility, kindness, charity, chastity, temperance, diligence and patience. Traditional Hindu weddings may include a grouping of seven promises. In literature, groups of seven include the seven dwarfs in the Snow White fairytale, and the seven novels in the Harry Potter series. In music, there are seven notes in a traditional major or minor scale.