The Seven Deadly Sins

I was wondering what the significance of the seven deadly sins is in the play; they enter with the devil when Faustus is doubting his decision to sell his soul. My first thought was that the addition of these seven demons was to add to the dark and sinister mood of the play (though some would argue that the mood is comic, and it is in some places) but as I read through the scene, I realized that they were meant to lure Faustus back into his dark path to destruction. Before the entrance of the sins, Faustus was doubting his pact with Lucifer, he was contemplating repenting to Christ and saving his soul. It was at this moment of strength against evil that the devil enters and ropes him back in by assuring him that Christ cannot save his soul. It is now that the sins (pride, avarice, lust, anger, gluttony, envy, and sloth) enter the play to entrance Faustus to return to his twisted path. They each introduced themselves and delighted Faustus.