What is the effect of an epistrophe?

epistrophe - repetition of the ends of two or more successive sentences, verses, etc.

eg Are we downhearted? - No we are not! Are we defeated? - No we are not! Are we depressed? - No we are not! eg from Shakespeare: She is a woman, therefore may be woo'd; She is a woman, therefore may be won; She is Lavinia, therefore must be lov'd.