Antithesis

Antithesis: establishes a clear, contrasting relationship between two ideas by joining them together or juxtaposing them, often in parallel structure. Human beings are inveterate systematizers and categorizers, so the mind has a natural love for antithesis, which creates a definite and systematic relationship between ideas.

E.g. Every man who proposes to grow eminent by learning should carry in his mind, at once, the difficulty of excellence and the force of industry; and remember that fame is not conferred but as the recompense of labor, and that labor, vigorously continued, has not often failed of its reward. --Samuel Johnson