parallelism

Parallelism in sentences refers to repeated grammatical structures. Elements in a sentence that have the same function or express similar ideas should be grammatically parallel, or grammatically matched. Parallelism is used effectively as a rhetorical device throughout literature and in speeches, advertising copy, and popular songs. Examples

Reading is to the mind what exercise is to the body. – Joseph Addison

Ask not what your country can do for you; ask what you can do for your country. – John F. Kennedy

government of the people, by the people, for the people, shall not perish from the earth – Abraham Lincoln