Redundant? The Church is the instrument ordained by Christ. The Church is an extension of His incarnation.
Extension: Something that can be extended or that extends to another object
Extended: Continued or prolonged
"A man’s body is all one, though it has a number of different organs; and all this multitude of organs goes to make up one body; so it is with Christ. We too, all of us, have been baptized into a single body by the power of a single Spirit, Jews and Greeks, slaves and free men alike; we have all been given drink at a single source, the one Spirit. The body, after all, consists not of one organ but of many...And you are Christ’s body, organs of it depending upon each other..." (1 Cor 12:12-30)
Christ had a body while on earth which He used to teach and sanctify. The Church is now an extension of His body, which is instructed to teach and sanctify. (cf. Mt. 26:26, Mt. 28:20)
The Church is the body of Christ and thus it is a divine institution. If the Church is not a divine institution, it is nothing more than a religious Elks Club.