He drew me up from the pit of destruction, out of the miry bog, and set my feet upon a rock, making my steps secure. He put a new song in my mouth, a song of praise to our God. Many will see and fear, and put their trust in the LORD. Psalm 40:2-3
A song in the heart is one of the surest evidences of a heart set free. Note the sequence of events here. Hopelessness and destruction. Sudden miraculous deliverance! Joy at being delivered!! Others noticing the joy and becoming aware of God’s greatness and trusting in God. The best hope of seeing someone converted is another person who has been converted. Why do you think joy is so critical in drawing others to Christ?