In Harry Potter and the Philosopher's Stone, when Harry first met Rubeus Hagrid in the Leaky Cauldron, he was surprised that Hagrid's giant hand didn't burn him when they shook hands. Hagrid explained that he had been expelled from Hogwarts School of Witchcraft and Wizardry for something he didn't do, and as punishment, he was forbidden from using magic. This meant he could not use protective spells or charms that would shield him from touching certain objects or people that might otherwise cause him harm, like Harry.