He doesn't. There is only one body of Christ. Denominations, sects, etc are man's invention.
Let me ask you a question - a serious one - there are probably well over a billion people who have never ever even heard of Christ, and billions and billions and billions more who came before us and never heard of Christ, where do they go and are they "saved"?????
This question has never been answered to me in a way that even remotely approaches something making sense.