The subject of this message is Jehovah as the Potter and Israel as the pottery. Jehovah is the Potter, and we, His chosen people, are the pottery in His hand.
As the Potter our God has the absolute right over us. Regarding us, He has the right to do whatever He likes. This thought is found not only in Jeremiah 18 through 20 but also in Romans 9. I believe that Paul was considering these chapters of Jeremiah as he was writing Romans 9 concerning God's sovereignty in His selection. In verse 21 he asks, "Does not the potter have authority over the clay to make out of the same lump one vessel unto honor and another unto dishonor?" God, the Potter, certainly has such authority. His selection is according to His absolute right. He may choose one vessel and reject another. He has the full right to do anything in any way to His pottery.
From Jeremiah's word in 15:10—17:27, we can see that there was something within him that was different from God's thought regarding Israel. I believe that the feeling within Jeremiah was that God's judgment upon Israel was too severe. At least he was not satisfied with the situation. In a sense, he was arguing with God. Instead of arguing with God directly, Jeremiah argued indirectly by expressing his feeling to his mother, saying, "Woe is me, my mother, because you bore me, / A man of strife and a man of contention to the whole land" (15:10a). This is a strong word. God did not give Jeremiah's mother an opportunity to respond but came in to speak with Jeremiah and even to argue with him. As God spoke to Jeremiah, He asked him, "Can one break iron, / Iron from the north, or bronze?" (v. 12). Here God was indicating that He was determined to use the Babylonians as iron to judge and punish Israel.
Following this section in which he tells of his experience of arguing with God, Jeremiah went on to write a section concerning Jehovah as the Potter and Israel as the pottery. This section makes it very clear that God is absolutely free to do whatever He desires to His people. He has the full right, just as a potter has the full right over the pottery. If we see this, we will be able to understand these three chapters.