Read Jeremiah 16-17 at Bible Gateway.
When Judah asks Jeremiah, Why is all this destruction coming upon us, the LORD tells him to answer them:
“Because your fathers have forsaken Me, they have walked after other gods and have served them and worshiped them, and have forsaken Me and not kept My Law. And you have done worse than your fathers, for behold, each one follows the dictates of his own evil heart, so that no one listens to Me.” Jer 16:11-12
Judah began to pick and choose which commandments to obey. They kept feast days and brought sacrifices, but they also worshiped idols and did not rest on the Sabbath day:
Thus says the LORD: “Take heed to yourselves, and bear no burden on the Sabbath day, nor bring it in by the gates of Jerusalem; nor carry a burden out of your houses on the Sabbath day, nor do any work, but hallow the Sabbath day, as I commanded your fathers. But they did not obey nor incline their ear, but made their neck stiff, that they might not hear nor receive instruction.” Jer 17:21-23
God is serious about His own definition of righteousness and sin as described in His Law — even the commands we may not understand like Sabbath keeping. We cannot decide, by the dictates of our own heart, what is righteousness and sin. We cannot decide that idolatry is sin, but working on the Sabbath day is righteousness. When we start making our own definition of righteousness and sin, we are following the dictates of our own hearts. When we obey God and incline our ears, and receive instruction, and allow God to define what is righteousness and sin, and agree with Him when He says, It is righteousness to hallow the Sabbath day and do no work on it, and it is sin to work on the Sabbath day, then we have taken heed to ourselves.
“The heart is deceitful above all things, and desperately wicked; who can know it?
I, the LORD, search the heart, I test the mind, even to give every man according to his ways,
According to the fruit of his doings.” Jer 17:9-10
When we let our own heart decide for us what is righteousness and sin, and we DO man’s ways and not God’s ways that He commanded in His Word, then that man is cursed – he has placed his trust in man and made flesh his strength. His heart has departed from the LORD, and is like a shrub in a parched place, bearing no fruit (Jer 17:5-6).
But when we let the LORD’s Word, which includes Exo 20 and Deu 5, decide for us what is righteousness and sin, and DO the LORD’s ways that He commanded for us in His Word, then that man is blessed – he has placed his trust in the LORD and made the LORD his hope (Jer 17:7). He shall be like a tree planted by the waters, and will not fear drought, for his leaf will be green and will not cease from yielding fruit (Jer 17:8).
Blessed is the man who walks not in the counsel of the ungodly,
Nor stands in the path of sinners,
Nor sits in the seat of the scornful;
But his delight is in the Law of the LORD,
And in His Law he meditates day and night.
He shall be like a tree planted by the rivers of water,
That brings forth its fruit in its season,
Whose leaf also shall not wither;
And whatever he does shall prosper. Psa 1:1-3
Let us not be deceived, church! If we heed the word of the LORD and obey Him, He will not bring disaster on us. But if we do not heed and do not obey, He will bring disaster on us (Jer 17:24-27). We can believe all the right doctrine, but the LORD determines whose heart is knit to His own heart, by obedience to His commandments (Mat 7:21-23, Joh 14:15, Rev 22:14). God’s Word is consistent from Genesis to Revelation — let us not be deceived!