Luther says:

 

The great difference between doctrine and life is obvious, even as the difference between heaven and earth. Life may be unclean, sinful, and inconsistent; but doctrine must be pure, holy, sound, unchanging ... not a tittle or letter may be omitted, however much life may fail to meet the requirements of doctrine. This is so because doctrine is God's Word, and God's truth alone, whereas life is partly our own doing.... God will have patience with man's moral failings and imperfections and forgive them. But He cannot, will not, and shall not tolerate a man's altering or abolishing doctrine itself. For doctrine involves His exalted, divine Majesty itself (WA, 30 111, 343 f.)

Strong words! But this is the spirit of confessional Lutheranism.