How did it ever go so wrong that Judaism became seen as a religion of external performance? At the giving of the Law we find these verses that show God is not simply interested in external obedience. His Law was a token of his relationship with his people, and that was to be in their hearts and woven into everything they did, every conversation that they had, everywhere they went.
“Love the Lord your God with all your heart,” says Deuteronomy 10:16. “Create in me a clean heart,” says David in Psalm 51. Judaism has always been about the heart, not just external obedience. The obedience must flow from the inside out.