The ending to the first Harry Potter book reflects themes that are found throughout the series: self-sacrifice, courage, friendship, and love. Harry would never have reached the Sorcerer’s Stone without help from his friends, and all three of them are risking both their lives and their places at Hogwarts, having been threatened with expulsion if they break any more rules. Their first priority is not themselves, but the people around them that will be in danger if Voldemort reaches the stone and returns to power. In the end, it’s Harry’s mother’s love that saves him, as it did once before and will several more times.
This is also the first of many last-second plot twists. We’ve been led to believe throughout the book that Snape was trying to kill Harry and steal the stone, but now it’s finally revealed that Quirrel was the guilty one, while Snape was in fact trying to protect both Harry and the stone. This is far from the last time Harry will jump to the wrong conclusions, miss the obvious clues right in front of him, and drag the reader with him in his misunderstanding of what’s going on. I actually really love this tendency of Harry’s. He’s an unreliable narrator, not because he’s intentionally misleading the reader, but because the narrator’s viewpoint is limited to only what he sees and thinks, which is more often than not an incomplete picture and a mistaken conclusion. This keeps the reader constantly trying to figure things out and sets us up to be surprised by the plot twists. Imagine how different things would be if the stories were told by a more well-informed character, such as Dumbledore, Snape, or even Hermione.