Scripture is clear enough to interpret itself

Lutherans confess the prophetic and apostolic faith as it has been handed down throughout the generations, but not because they see that earlier Christians did so. Interpreting Scripture in light of what earlier Christians say is a very dangerous procedure, for Arianism preceded the Nicene Creed, and first-century false teachers preceded both.

For Lutherans, Scripture interprets Scripture, that is, clear passages shed light on unclear passages. Otherwise, Scripture would be so unclear that it would require interpretation by human reasoning, whether that be one’s own reasoning or the reasoning handed down in one human tradition or another.