in Jer.18:18-23 We have a time where Jer. is doing good to the people to help them find the Lord. The people are rejecting his words and God also. He is noticing they don't want to hear him anymore, so they are preparing to harm him. v.20 and 22 show that they are so agitated that they are preparing to put him where (Barnes O.T. commentary) says they want to put him in a pit where you put dead animals. You can see by reading the former part of the chapter 18 that God is angry with them to the point of putting them to death. Now they want to put Jeremiah to death. Jeremiah is a real picture of Christ. In 18:20 The pit they want to put Jeremiah in is a literal place. Notice in Jer. 18:20 the pit they will put him in is for his soul. His whole person. This is because the soul person of Jer. is speaking words they don't want to hear. They are devising mischievious devices against him. v.18 we see he is a living soul here.