[I]f you have a purpose in which you can believe, there's no end to the amount of things you can accomplish.

The remark links achievement less to raw talent or circumstance than to conviction and direction. “Purpose” suggests a guiding aim—artistic, moral, or civic—that organizes effort over time; “believe” implies an inner commitment strong enough to withstand setbacks and external discouragement. Read this way, the quote argues that sustained accomplishment grows out of meaning: when a person’s work feels necessary and justified, persistence, discipline, and risk-taking become easier, and the range of possible outcomes expands. It also carries an implicitly uplifting, self-determining message often associated with inspirational speech: clarity of purpose can convert obstacles into endurance rather than resignation.