All the stories of the Old Testament relate truths of the new testament to us in object lesson form.
Esther solved the problem of Haman's plans to destroy the jews... so she thought.
Initially Haman was hanged on the gallows made for Mordecai. That alludes to the cross where satan's desire to destroy Christ actually brought his own destruction.
But after Haman was gone, the law the man set forth to destroy Jews on Adar the 13th was still in effect. Haman was hanged but his law still existed.
This is precisely the dilemma of believers. The devil's power is subjugated b the cross. But the law of sin and death still hangs out there over too many believers' heads. Esther's answer was provided by the king. The law cannot be undone. But it can be overcome by a higher law. Use the king';s name for a HIGHER LAW and render the law of Haman ineffective. But if you do not use this higher law and the King's name, suffer the consequences.
This is like the law of sin and death. It will mess believers up unless they live by the HIGHER LAW of the Spirit of Life in Christ Jesus. So long as one trusts in God in faith and relies on His spirit to empower us, the law of sin and death cannot prevail. But stop living like that, and succumb to the law of sin and death.
This is how
Romans 7 can affect a Christian.