Romanos 9:19

‘You will say then to me, “Why does he still find fault? For who withstands his will?” '

He opens with a theoretical argument, although no doubt one he had heard many times, that of someone who says, “(If God hardens whom He will) why does he still find fault? For who withstands his will?” The idea behind the argument is that if God is sovereignly responsible for men's decisions, no blame can be laid on men for how they respond to Him. All they are doing is fulfilling His will. Thus it would be unfair of God to find fault with them.