God changes hearts through the Gospel of Christ. What happens when God changes our hearts? The heart is an expression for our inner person. That's our mind, will, and emotions. The Spirit of God changes our hearts to confess Jesus is Lord (Ro. 10:9; 1 Cor. 12:3). God's Spirit enables us to know Christ in a very personal way.
God changes our mind. God renews our mind to understand spiritual things that are taught in the Bible, "by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God" (Ro. 12:2). The Holy Spirit is our teacher, giving us more and more understanding through the Bible.
God changes our will. God "works in you both to will and to do for His good pleasure" (Philippians 2:13). We are then willing to do God's will, with a desire to serve Him and minister to others for His glory. We become doers of the word and not hearers only (James 1:22).
God change our emotions. We then have a godly sorrow for our sins. We are moved with compassion to help others. Perhaps we may feel a burden to pray for someone. Remember that God does the work in our hearts, and that includes our emotions.