Paul is talking to the critics of his teaching as though his is talking to one person. You may need to use the plural here. (See: [[rc://en/ta/man/translate/figs-youdual]])
Paul uses the potter's right to make any kind of container he wants from the clay as a metaphor for the creator's right to do whatever he wants with his creation. (See: [[rc://en/ta/man/translate/figs-metaphor]])