How we cite our quotes: All quotations are from Harry Potter and the Sorcerer's Stone.
Quote #7
MCGONAGALL: In a few moments, you will pass through these doors and join your classmates. But before you can take your seats you must be sorted into your Houses. They are Gryffindor, Ravenclaw, Hufflepuff, and Slytherin. Now, while you are here, your house will be like your family.
Just an early emphasis on how important your Houses are in this world…and by extension, how much the Houses will dictate the kind of experience you'll have at Hogwarts.