What does the Bible say about grace being essential for a believer's heart?

Hebrews 13:9 emphasizes the importance of being established in grace as opposed to being occupied with the ceremonial law, which can never truly settle the conscience or bring peace. The heart of a true believer understands the inability to achieve righteousness through the law and thus finds comfort and stability in the grace of God that is found in Christ alone. Salvation is not about adhering to the law, but instead, it is about relying on the finished work of Jesus Christ. This understanding enables the believer to live confidently and joyfully, secured by grace.