Does God Actually Harden Some People Against Himself?

After Paul’s statement in Romans 9:16 that man’s salvation does not depend upon his own desire, or his own effort, he continued his teaching of election and God’s sovereign choice of a people. Paul emphasized God’s decision to save those individuals to whom He has decided to show mercy, and he also taught that God chooses not to show mercy to others, even hardening
them against His will. Paul wrote: “For the Scripture says to Pharaoh, ‘For this very purpose I raised you up, to demonstrate My power in you, and that My name might be proclaimed throughout the whole earth.’ So then He has mercy on whom He desires, and He hardens whom He desires.” (Romans 9:17-18).
Here Paul used the example of Pharaoh, whom God hardened against His will and against the request of Moses to let the people of Israel go from their bondage in Egypt. As Paul quoted from Exodus 9:16, God hardened Pharaoh against Himself in order that He might show His power and that His name might be proclaimed in all the earth by the miracles He wrought through His servant Moses when He brought His people out of Egyptian bondage by His own might and power.
God hardened Pharaoh against Himself and accomplished His own purpose through it.
One might ask: well why did God harden Pharaoh; why did He not just show mercy to Pharaoh and make him willing to obey Him? God does not reveal His “reasons” why He chooses to harden some, and He chooses to show mercy to others. However, it is revealed to us that God’s mercy shown to those whom He calls to faith in His Son has nothing whatsoever to do with their own works, and therefore no man can boast that he obtained God’s favor by his own actions (Ephesians 2:9-8, I Corinthians 4:7). The fact remains, as Paul taught in Romans 9:18, that God has mercy upon whom He wants to have mercy, and He hardens those whom He wants to harden.