Gerhard O. Forde writes:
The theologian of glory is like one who considers, curing addiction by optimistic exhortation. The theologian of the cross knows the cure is much more drastic. [Luther] likens the theology of glory to the thirst, for money, or wisdom, or power, and so forth, and declares that the souls insatiable “thirst, for glory does not end by satisfying it, but rather buy extinguishing it.
And breezily telling someone they can quit sin and giving them more things to do doesn’t help. In fact, it makes things worse.
The supposed optimism of the theology of glory turns against itself. When the addict discovers the impossibility of quitting, self-esteem plummets. The addict to tries to hide the addiction and puts on a false front. Superficial optimism breeds ultimate despair.