Sometimes we see Heaven depicted as a place where people sit around on clouds, strumming on their personal harps in boredom. While it is true there will be harps in Heaven, not everyone will be playing them. In Revelation 14:2, John the apostle was describing a stringed instrument. It was a point of reference for him: "And I heard a voice from Heaven, like the voice of many waters, and like the voice of loud thunder. And I heard the sound of harpists playing their harps."
Maybe we could update this scene in Heaven by saying there were a lot of guitarists rocking out on their electric guitars. The point is that it isn't boring; it is a celebration of a new song that is being sung.
Every believer should have a new song. The psalmist David wrote, "He also brought me up out of a horrible pit, out of the miry clay, and set my feet upon a rock, and established my steps. He has put a new song in my mouth—praise to our God; many will see it and fear, and will trust in the Lord" (Psalm 40:2–3).
If you have trusted in Christ, if you have been lifted from a pit of despair, then you have a new song. Did you know that? It doesn't need to be a literal song. You don't have to walk around and sing, "I used to be an unbeliever . . . but now I am a Christian. . . ." Rather, it is the idea of having a new message.
So stop singing the old song. Sing the new song. Let others know what Christ has done for you. That is what these believers in Heaven were doing. And that is what we ought to do.