Whatever you can do, or dream you can, begin it. Boldness has genius, power and magic in it.
Starting is the hard part, and this line says the starting itself holds the force we keep waiting for. Many of us hold back until we feel ready or certain, as if confidence has to arrive first. The quote reverses that order. Boldness is not a reward for finishing the preparations. It is what calls up "genius, power and magic", meaning the ideas, energy and unexpected help that tend to gather once we commit.
The attribution to Goethe is disputed. These exact words are generally thought not to be his, and they read like a loose English paraphrase of his spirit. Still, they fit his outlook, especially in Faust, where a person is defined by restless striving and action rather than by passive contemplation. For Goethe, a life lived fully means venturing something, not waiting on the sidelines.
Imagine someone who has long dreamed of writing a book but keeps postponing it until life calms down. Following this advice, they might write one rough page tonight, or show a paragraph to a friend. The act is small, but it turns them from a person who thinks about writing into a person who writes, and momentum usually follows from there.