The Northern Kingdom of Israel fell to the Assyrians in 721 BC. They had turned from the God that delivered them from Egypt to serve the pagan gods in the land that God had given them and that they had failed to drive out. Many of the Old Testament prophets exposed 
the sins of Israel as the cause of their destruction. They had become a wicked nation and God allow her behavior to have its consequences. The Southern Kingdom had fallen away also. Jeremiah says they were even worse than Israel. In Jeremiah 3:9-11 he says, speaking of Israel, “Because she took her whoredom lightly, she polluted the land, committing adultery with stone and tree. Yet for all this her treacherous sister Judah did not return to me with her whole heart, but in pretense, declares the LORD. And the LORD said to me, Faithless Israel has shown herself more righteous than treacherous Judah.”
It seems like God declared Judah’s rebellion worse than their Northern sister’s rebellion for two reasons. First, Judah failed to learn from what had happened to Israel. She saw it and didn’t take it seriously. The second reason seems to be Judah’s pretensions of righteousness. She kept rituals and gave lip service to regulations and practices but did not truly have a pure “heart” for God. One commentator says, “God wants our love, as we want the love of our children and of our friends, and cannot accept anything, however valuable, in its stead: so Christ wants the pure, deep, lasting affection of our souls. No ceremonies, or services, or even sacrifices, will compensate for its absence (see 1 Cor. 13). And the measure of our love will depend on the depth of our sense of God’s forgiving love toward us.”[1]
Susan Maycinik wrote, “The line between obedience and performance can be a blurry one. Yet it is an important distinction to grasp, because obedience leads to life, and performance to death. Obedience is seeking God with your whole heart. Performance is having a quiet time because you’ll feel guilty if you don’t. Obedience is finding ways to let the Word of God dwell in you richly. Performance is quickly scanning a passage so you can check it off your Bible reading plan. Obedience is doing your best. Performance is wanting to be the best. Obedience is saying yes to whatever God asks of you. Performance is saying yes to whatever people ask of you. Obedience is following the promptings of God’s Spirit. Performance is following a list of man-made requirements.”[2]
[1] H. D. M. Spence-Jones, ed., St. Luke, vol. 1, The Pulpit Commentary (London; New York: Funk & Wagnalls Company, 1909), 194.
[2] Craig Brian Larson, 750 Engaging Illustrations for Preachers, Teachers & Writers (Grand Rapids, MI: Baker Books, 2002), 371–372.