Having answered the charge concerning God’s justice, Paul now deals with objections against His sovereignty. To do so, Paul uses the image of a potter (God) and the pots He makes from the clay that He has. Some of the clay He forms into pots for noble purposes, whilst from the same lump He forms some into pots for ignoble uses. The whole lump of clay represents fallen humanity.
The clay that is left in its fallen state has no right to complain against the potter who takes some of the clay and forms it into vessels of glory. So those who are condemned for their sin cannot blame the sovereign God because they freely rejected His offer of salvation.
In a similar manner, the vessels of honor cannot boast in themselves, because God has formed them for honorable purposes according to His will and not because of their merits.