What does the Bible say about justification and sanctification?

Justification is the act by which God declares a sinner righteous based on faith in Jesus Christ. The Heidelberg Catechism reinforces this, stating that we are made right with God solely through faith in Christ, despite our ongoing sinfulness. Sanctification, on the other hand, is the ongoing work of the Holy Spirit in the believer's life, leading them to live righteously. Confusing these two concepts can lead to legalism or a dependence on works for righteousness, which is contrary to Scriptural teaching. Scriptures like James 2:26 emphasize that faith without works is dead, yet clearly articulate that our justification is through belief in Christ alone (Romans 5:1).