f you wanted to stop sinning, what part of your being would you employ? Your heart/thinking/will. But Jeremiah is saying you can’t use your heart to clean your heart. Because it is tainted by the sin too. That is like trying to wipe a spot of gravy off your couch with an oily rag.
Clint Archer has posted informative and fascinating insights into John Calvin’s TULIP doctrines. This one is on Irresistible Grace. As I said, informative and fascinating.