The devil is a Christian name to call Lucifer and it denotes ultimate evil.
I had a major problem with that speech she had with Father Faustus in that they wanted Sabrina to be the fish out of water representing the Christian world talking to someone representing the Witch world. Her comments would have made sense for someone who attended a Christian church until 16, but no sense with Sabrina's upbringing.
Her comment that the devil is the ultimate evil to Faustus is case and point of moments where they stripped Sabrina from her background in the supernatural world where she was raised to see the Dark Lord as her deity (and she was given her casual comments throughout the show 'Satan Bless Us', 'Satan help me I will tear you apart' and so on) and she is suddenly given the role a church going Christian who knows jack squat about the witch world or basic witch beliefs and ethics about their deity (and her deity).
I understand as a writer myself why it happened given the decision to keep Harvey and all her other friends in the dark about the witch world so you couldn't have a voice of the normal Christian world commenting on the witch world until the end of the season outside the little speech between Harvey and Sabrina she erased.
But, having Sabrina suddenly not know the very basics about witches and their customs and traditions really tossed me out of the story over and over again season one. It was the biggest problem for me in an otherwise great season. Hopefully season two manages to fix this problem now that you have several mortals around who can be the fish out of water representatives of the Christian world.