The story of the Shadrach, Meshach, and Abednego is one of the Bible's best (Daniel 3). Three young men, exiled far from home, are commanded at the sound of the music to bow to the Babylonian gods. Refusal to do so would result in their death.
In a limited sense, Nebuchadnezzar, king of the Babylonian empire, had every right to make this demand. He was, after all, the king of the realm. All subjects owed their obedience to him. In this limited view, we understand that what is good for the king is good for the subjects of the king.
Of course, we realize that Nebuchadnezzar was never an ultimate king. He was local, and temporary. Nonetheless, the predicament of the three young men is gripping. Their refusal to bow down is noted, reported, and warned. They are mercifully given a second chance. Their response is inspiring: “O Nebuchadnezzar, we do not need to give you an answer concerning this matter. If it be so, our God whom we serve is able to deliver us from the furnace of blazing fire; and He will deliver us out of your hand, O king. But even if He does not, let it be known to you, O king, that we are not going to serve your gods or worship the golden image that you have set up.”
Now we come to Christian worship in the local church. God, the Sovereign King, is gathering His people to praise His holy name. And, it is reported that there are some who refuse to sing. They may reply that they do not sing because of lack of voice, or unfamiliarity with the song, or a preference for some other instrument or style. Maybe you are just not in the mood. But these things matter little when God's people is gathered and given opportunity and obligation to render praise to their God.
We are not God's police force. We are glad that you are present. But we are gathered to worship God. The most important person in the room is not you, but God, present by His Spirit. The most important pleasure in the room is not yours, but God's. He is pleased when His people praise.
Isaac Watts, the English hymn writer, wrote the line that is used in the title: "Let those refuse to sing, who never knew our God." If you know Him, sing. If you wish to praise Him, sing. If you want to know Him, sing!"