Definition and Etymology:
Righteousness, in the biblical context, refers to the quality of being morally right or justifiable. It is derived from the Hebrew word "tsedeq" and the Greek word "dikaiosyne," both of which convey the idea of justice, virtue, and uprightness. Righteousness is a central theme in the Bible, reflecting God's character and His expectations for human conduct.

Old Testament Context:
In the Old Testament, righteousness is often associated with adherence to God's laws and commandments. It is seen as a covenantal relationship between God and His people, Israel. For instance, Genesis 15:6 states, "Abram believed the LORD, and it was credited to him as righteousness." Here, righteousness is linked to faith and trust in God.

The Psalms and Proverbs frequently highlight the blessings of living a righteous life. Psalm 1:6 declares, "For the LORD guards the path of the righteous, but the way of the wicked will perish." Righteousness is portrayed as a path that leads to life and divine favor.

New Testament Context:
In the New Testament, righteousness takes on a more profound theological significance, particularly in the writings of the Apostle Paul. It is closely associated with the concept of justification by faith. Romans 3:22-24 explains, "And this righteousness from God comes through faith in Jesus Christ to all who believe. There is no distinction, for all have sinned and fall short of the glory of God, and are justified freely by His grace through the redemption that is in Christ Jesus."

Jesus Christ is the ultimate embodiment of righteousness. His life and teachings provide the perfect example of righteous living. In the Sermon on the Mount, Jesus emphasizes the internalization of righteousness, urging His followers to seek a righteousness that surpasses that of the Pharisees (Matthew 5:20).

Theological Significance:
Righteousness is not merely about external compliance with the law but involves a transformation of the heart. It is a gift from God, imputed to believers through faith in Jesus Christ. This imputed righteousness is foundational to the doctrine of justification, where believers are declared righteous before God because of Christ's atoning sacrifice.

The Apostle Paul further elaborates on this in Philippians 3:9, stating, "And be found in Him, not having my own righteousness from the law, but that which is through faith in Christ—the righteousness from God on the basis of faith."

Practical Implications:
For Christians, understanding righteousness involves both positional and practical aspects. Positional righteousness refers to the believer's standing before God, justified by faith. Practical righteousness involves living out one's faith through actions that reflect God's character and commands.

James 2:24 underscores the importance of works in demonstrating genuine faith: "As you can see, a man is justified by his deeds and not by faith alone." Thus, righteousness is both a gift received and a life lived in obedience to God's will.

Conclusion:
Righteousness is a multifaceted concept that encompasses God's nature, the believer's justification through faith, and the ethical conduct expected of those who follow Christ. It is both a divine gift and a human responsibility, calling believers to reflect God's holiness in their daily lives.