What does it mean to have God's testimony in our hearts?

When believers have God's testimony in their hearts, it indicates that the truth about Jesus Christ and His work of salvation is embedded within them. According to 1 John 5:10, this internal testimony transforms one's identity and perspective on life. The Holy Spirit works to make this truth alive and active in the believer, ensuring that it cannot be discarded or exchanged for something else. This deep-rooted truth shapes their beliefs, actions, and responses in life, affirming that being a Christian is not merely about outward practices but involves an inner conviction derived from God's revelation.