The White Rabbit keeps saying “Oh dear! Oh dear! I shall be too late” near the start of the novel.
Alice first notices him in Chapter I, “Down the Rabbit-Hole,” while sitting beside her sister. His unusual appearance—a waistcoat, a pocket watch, and hurried behavior—immediately signals that Wonderland will operate by strange rules.
Alice follows him down the rabbit hole, beginning her adventure. The Rabbit later mistakes Alice for his housemaid, Mary Ann, and sends her to his house. He also serves the King and Queen of Hearts as a herald-like figure near the end of the book.
Readers sometimes confuse this scene with the Disney film’s expanded “I’m late” song. Carroll’s original wording is shorter and more anxious, and the character is specifically the White Rabbit, not the March Hare or another royal-court figure.