What is defined as the legal term that changes the believing sinner's standing before God?

The term that best describes the legal change in a believing sinner's standing before God is justification. Justification refers to the act by which God declares a sinner to be righteous on the basis of faith in Jesus Christ. This change is legal in nature, meaning that it pertains to God's judgment regarding a person's status. When someone accepts Christ, their sins are forgiven, and they are declared righteous, thereby altering their standing from one of guilt to one of acquittal.

Sanctification, while an important process of spiritual growth and holiness after one is justified, does not refer to the initial legal standing before God but rather to the ongoing transformation that occurs in a believer’s life. Regeneration pertains to the spiritual birth or renewal that occurs during conversion, which enables a person to have faith in Christ but does not itself change their legal status. Redemption speaks to the overall act of being bought back or saved, particularly from sin and its consequences, but justification specifically addresses the legal declaration made by God concerning an individual’s righteousness.