Redundancy

Iteration of an idea has a long and honored history in the English language, and is used for emphasis. Some good examples, which are usually found in formulary speech are: "It is fitting and proper . . ." "A good and wholesome . . ."

Basically, the iteration serves as an intensifier. Your example, does, however, show how little logic actually controls speech, and also, how little need there actually is for logical structure in order to logically communicate meaning.