No amount of darkness can resist even a small flame. Krishna says: even if you were the worst sinner among all sinners, the boat of knowledge alone would carry you across all wrongdoing. The past does not have to define the future. What matters is the knowledge that arrives now.
This is among the most hopeful declarations in the entire Gita. It says that no one is beyond redemption. No history of mistakes, no weight of accumulated wrongs, is so heavy that knowledge cannot lift it. The boat does not ask who climbs aboard. It simply carries anyone willing to step in.