Christians are very divided among each other; should that not be different?

Luther:

Christians are not divided, but one in Christ (and through Him with the Father). How? Not through our works, but through the Word that He has given us. Through our works there arise all sorts of separate sects and schisms, because one does now this way, and the other that way. So it is also in daily life: everyone has his own profession and way of working. But through the Word everything becomes one in faith, and because of that they are also one spiritual body, even if their works differ.