“Hypocrites in Your Hearts” is how the NKJV translates Jeremiah’s charge against the people in Jer. 42:20. The KJV says that they were “dissembling in your hearts.” The NASB says that they had “deceived yourselves,” and the ASV says that they were acting “deceitfully against your own souls” Additionally, the NIV calls it a “fatal mistake.” All of these carry the idea of a people who are lying hypocrites - not just in their dealings with others and God - but even with themselves. What occasion brought such a charge?
It was aimed at the remnant of God’s people who had come to ask Jeremiah to pray for them in a time of great difficulty. They had a perfectly worded expression of devotion to do whatever God revealed. “...Please let our petition come before you, and pray for us to the LORD your God, that is for all this remnant; because we are left but a few out of many, as your own eyes now see us, that the LORD your God may tell us the way in which we should walk and the thing that we should do.” (Jer. 42:2,3) Should they stay or should they go? They submissively replied, “We’ll do what God says!”
The problem they had already made up their mind as not only what they wanted to do, but had actually begun to do it. Before they ever thought to seek the Lord’s counsel they had already started heading to Egypt! “And they went and stayed in Geruth Chimham, which is beside Bethlehem, in order to proceed into Egypt.” (Jer. 41:17)
This attitude (of doing first and asking God later) is wicked, open, knowledgeable, purposeful, rebellion to God. They only pretend to consider God’s will. Only pray after they’ve already decided.