Kierkegaard claims that Christendom reads the Gospels all wrong — it's as if everyone skipped to the end, found out Jesus was in fact God, and then read what it has to say. But, for Kierkegaard, what makes Christianity what it is is that you don't know that Jesus is God — you believe it, or don't.
When reading the Gospels, Kierkegaard tells us that we must be contemporary with the text, contemporary with Jesus and the disciplines. From that perspective, the text is insane and the demand even more so: believe that a singular, historical man is the eternal God. Nuts.
And, for Kierkegaard, this critique turns on hermeneutic posture: how do you stand towards a text and the demands it makes?