Yahweh is speaking. The Hebrew text is not clear in various places. However, many people interpret it as describing the royal officials as being unfaithful to God, and also as planning to assassinate the king, and then carrying out their plans. This seems to have happened more than once. These crimes are mentioned as illustrations of the wickedness into which the nation has sunk.
The people committed spiritual adultery by worshiping idols and being unfaithful to Yahweh. They were probably also being unfaithful to their husbands or wives by sleeping with other people. (See: [[rc://en/ta/man/translate/figs-metaphor]])
This can be stated in active form. This means the people had strong desires to do evil. AT: "like an oven which the baker heats" (See: [[rc://en/ta/man/translate/figs-simile]] and [[rc://en/ta/man/translate/figs-activepassive]])
This probably means to unite or join with someone. It may mean that the king joins with his officials to mock things or people that should not be mocked, even God himself. (See: [[rc://en/ta/man/translate/figs-idiom]])