Hath not the potter power over the clay, of the same lump to make one vessel unto honour, and another unto dishonour?
Note 12 at Ro 9:21: Paul was drawing an illustration from an Old Testament passage of Scripture, Jer 18:3-6. In that passage, God sent Jeremiah to the potter's house to learn a lesson. The potter was making a vessel; it was marred, so he remade it. The Lord spoke to Jeremiah and said, "O house of Israel, cannot I do with you as this potter?...Behold, as the clay is in the potter's hand, so are ye in mine hand, O house of Israel" (Jer 18:6).
From this illustration, some people have drawn a wrong conclusion that the Lord creates some people evil and predestined to a life of damnation, not by their choice, but by God's. However, a closer look at the passage in Jeremiah and its context will show that is not the case.
First of all, the potter started to create a good vessel, but the clay was marred. Whose fault was that? It wasn't the potter's fault. The clay was faulty. The potter took this imperfect clay, and instead of discarding it, he refashioned it into another vessel that may not have been worth nearly as much as his original design but was still useful.
Likewise, the Lord does not create certain individuals for destruction. However, some do become marred by their own choices, not due to any fault of the Creator. Instead of just removing them from the earth, the Lord will endure (Ro 9:22) their atrocities. He may even put them in great positions of authority, such as He did with Pharaoh, so that He may manifest His great power through His victory over them and their devices. God can still use someone who has rejected Him, in the same way that a potter can take a marred piece of clay and find some use for it.
By continuing to read the context of Jeremiah's experience with the potter, it can be clearly seen that the Lord does not do these things against the will of the individual. In Jer 18:7-10, the Lord said that when He purposes evil or good against a nation, if that nation repents, then God will change His plans for them. That undeniably states that man's choice influences God's choice.