In the Bible, the word heart is often a figure of speech for the mind, will, and emotions. God's work of grace is performed in your heart by the Holy Spirit. Through the gospel of Christ, God changes your heart. That is to say, God changes your mind, will, and emotions.
God changes your mind by the Holy Spirit (Romans 12:1-2). Then we understand the power of the gospel (Romans 1:16). We repent and receive Jesus as our Lord (1 Corinthians 12:3). Repentance means a change of mind. That change is enabled by the Holy Spirit changing our hearts (Romans 2:28-29).
God changes your will with new desires. Once we had no desire for Christ. We were unwilling to receive Christ. Now, God has worked in our hearts with a desire for Christ (Philippians 2:13). That's the work of God in our hearts through the Holy Spirit (Philippians 1:6).
God changes your emotions. Once we had no tender emotions toward Christ nor remorse for our sins. Now, we have godly sorrow for our sins, and emotions of love and gratitude toward Jesus Christ (1 Corinthians 16:22; 2 Corinthians 7:9-10).
