What are the origins of the seven deadly sins?

The medieval church liked sevens—the seven joys of Mary, the seven gifts of the Holy Spirit, the seven deadly sins, the seven cardinal virtues, the seven liberal arts. Seven was just part of the Zeitgeist, and so the deadly sins were organized into seven.

Vanity, Sloth, Envy, Lust, Greed, Gluttony, Wrath.

Oh.

If you google the number seven, you get the information that it is a very strange number. The Greeks thought it magical; and it does appear that practically everybody thinks so too. Hence: seven deadly sins, seven virtues, seven against Thebes, seven wonders of the ancient world, etc.