David S. Yeago on "The Catholic Luther"

"There is, in fact, a driving question in Luther's early theology, but it is not the question of the assurance of forgiveness. The troubling question that emerges from the preoccupations of the young Luther's thought is not "How can I get a gracious God?" but "Where can I find the real God?" All the evidence in the texts [Luther's writings] suggests that it was the threat of idolatry, not a craving for assurance of forgiveness, that troubled Luther's conscience if anything did. And this question did not, as some of Luther's interpreters have been eager to believe, burst the framework of traditional Christianity; both the emergence of the problem itself and Luther's eventual solution to it locate him precisely within the catholic tradition."

- Take from The Catholicity of the Reformation; chapter 2, "The Catholic Luther" by David S. Yeago.

First Things actually published an article by David S. Yeago titled "The Catholic Luther". If you are interested in reading the article, and I do recommend it, then you can read it here.