How do we know God's goodness and mercy is true?

The assurance of God's goodness and mercy is grounded in His unchanging nature and the testimonies of His faithful actions. David, despite his imperfections, exemplified a humble confidence in God's promise, recounting victories like his triumph over Goliath. Similarly, every believer can reflect on the moments where God's grace was evident in their lives—times of answered prayers or spiritual restoration. God has proven His faithfulness repeatedly, and through the work of the Holy Spirit, we are assured that His goodness and mercy are ever-present.