In God's worship, should everyone be in one accord, like everybody doing the same thing? I ask because I know there shouldn't be musical instruments in the church. I play the piano and people have told me that I was wrong because I didn't play in a church -- something about me not using the gift He gave me. I told them God didn't command it, we all should sing. If you blow a horn, you're not singing, are you wrong? A friend of mine also told me he uses instruments not as a commandment or worship practice but as an addition to have the music sound better. I told him it's still wrong because it's not what He asked. Well, he feels that if it's a way to praise God, then it's not wrong. So his church has a dance team, flag performances and even on some Sundays have something called crazy praise. I really don't know how to talk to him to have him understand.
"If you love Me, keep My commandments. ... He who has My commandments and keeps them, it is he who loves Me. And he who loves Me will be loved by My Father, and I will love him and manifest Myself to him. ... If anyone loves Me, he will keep My word; and My Father will love him, and We will come to him and make Our home with him. He who does not love Me does not keep My words; and the word which you hear is not Mine but the Father's who sent Me" (John 14:15, 21, 23-24).
Love for Christ is demonstrated by our willingness to do as Christ commanded us. Your friend, however, has turned this around. He claims that anything he decides praises God is something God will accept. Thus he puts his own personal preferences in the driver seat above God. As Paul noted, "For do I now persuade men, or God? Or do I seek to please men? For if I still pleased men, I would not be a bondservant of Christ" (Galatians 1:10). Worship is not about pleasing ourselves. It is about man bowing to God's will and serving Him. "Let us hear the conclusion of the whole matter: fear God and keep His commandments, for this is man's all" (Ecclesiastes 12:13).
Your friend admitted that instrumental music was not authorized, but he wanted them as an addition in order to make the music sound better. Sound better to whom? If a bride asked for acoustic guitar music at her wedding and the musicians brought in electric guitars, keyboards, drums, etc. to play heavy metal, did they show respect for the bride? Can they claim that the extra equipment would make the music sound better? Again, sound better to whom?
God has never taken innovations by men as a matter of complimenting Him.
""Woe to the rebellious children," says the LORD, "who take counsel, but not of Me, and who devise plans, but not of My Spirit, that they may add sin to sin"" (Isaiah 30:1).
"You shall not add to the word which I command you, nor take from it, that you may keep the commandments of the LORD your God which I command you" (Deuteronomy 4:6).
"Whatever I command you, be careful to observe it; you shall not add to it nor take away from it" (Deuteronomy 12:32).
"Do not add to His words, lest He rebuke you, and you be found a liar" (Proverbs 30:6).
"I marvel that you are turning away so soon from Him who called you in the grace of Christ, to a different gospel, which is not another; but there are some who trouble you and want to pervert the gospel of Christ. But even if we, or an angel from heaven, preach any other gospel to you than what we have preached to you, let him be accursed. As we have said before, so now I say again, if anyone preaches any other gospel to you than what you have received, let him be accursed" (Galatians 1:6-9).
"For I testify to everyone who hears the words of the prophecy of this book: If anyone adds to these things, God will add to him the plagues that are written in this book; and if anyone takes away from the words of the book of this prophecy, God shall take away his part from the Book of Life, from the holy city, and from the things which are written in this book" (Revelation 22:18-19).
Whether your friend cares is a demonstration of his heart.