Is this a first post?

Your stay here will be short.

That's not very nice, Paix.

Actually, I get asked similar questions all the time, and have asked them of myself on occasion. Psalm 150 in particular first came up for me in a conversation with the Protopsalti of a local Antiochian Orthodox church, who believes that the organ, and any musical instruments, are inappropriate in the context of a Mass or Divine Liturgy. Though I don't agree, we reached consensus on several points.

First, we should indeed praise the Lord with trumpet, harp, lyre, drum, dancing, and everything else we do. We should praise Him in our every action. That doesn't necessarily mean we should employ every technique of praise at every moment. Besides being impossible, certain things are more fitting in particular circumstances than others. Long personal testimonials might be fantastic, for example, but Mass might not be a good setting for them. Similarly, praise with drums and dancing might fit best during some time other than Mass. So, leaving the trumpet out of Mass doesn't mean we are ignoring something we are explicitly instructed to do.

Second, the Psalms are themselves songs, literary works, emotional and expressive. The Psalms are a different genre than, say, the Ten Commandments or the Sermon on the Mount. Though they too of course are inspired, and authoritative, it's not clear that their injunctions should be interpreted as explicit commands. This was not a command that says: "Worship only by using the trumpet, the lyre, the harp, and the drum." It really would be reading too much into the text to say that Psalm 150 mandates the use of instruments, and any worship that doesn't employ them falls short.

Third, there is a case to be made that the most perfect musical instrument of praise is the human voice, which is what the Orthodox believe. Because I am not entirely on board, I won't attempt to summarize it here, lest I sell it short. Regardless of whether you find it convincing, it is extremely difficult to argue that 100% vocal music is INAPPROPRIATE, or unfitting. Perhaps instruments are just as acceptable, but how can purely vocal music be LESS fitting? If a community doesn't happen to have any instruments, their praise is somehow less perfect? That doesn't make much sense. To say unaccompanied chant, because of the lack of instruments, is inappropriate, doesn't follow.

Now you are right, the organ isn't specifically mentioned in Psalm 150. But the organ wasn't invented yet. AND, Psalm 150 wasn't trying to compile a formal list, it was an expression of exuberance. So, to argue that Psalm 150 tells us to use the trumpet, etc., but NOT the organ, so the organ is inappropriate, is poor exegesis.

If you want to make the case that chant and organ are the ONLY forms appropriate to Mass, the argument would have to have several parts: 1) chant best achieves whatever purpose music is supposed to have at Mass; 2) the human voice best suited or most appropriate for the purposes of Mass; 3) the organ is extremely similar to the human voice, and so, if there is going to be an instrument, it should be that one. 4) other instruments, whether due to particular inherent traits, or due to our associating them with secular situations (like the sax with lounges), might be less suited. I myself am not making that argument, I'm only sketching what it would look like.

Make sense?

There are a lot of ways in which Catholic worship differs from Jewish worship in the Temple. We don't use blood sacrifice, for one. Roman rite Catholics use incense like Temple worship did, but not all early Christians did (e.g. those in Palmyra). If the words had been written by St. Paul rather than by the psalmist, that kind of exhortation would be much more normative to Christian worship.

I think it is beyond question (pace Gavin) that the psalms were originally set to the lyre, just like ancient Greek epic was originally. That doesn't mean that when Christians used them in a distinctly Christian worship that there were to be used only as originally intended.

Are the people who are making the case to use lyre, drums, etc. also lobbying for a return to proclaiming them in Hebrew?

Until the church decides its music documents are worth enforcing, it is going to be difficult for anyone else to take them seriously. Oh, I know, many folks can quote those documents until they are blue, but the documents are worthless for any practical purpose. I think bad church music is like pornography - you know it when you hear it.

Let me add some thoughts about how arguments such as the ones put forth two days ago by Daniel should be met. I once agreed with those views, and actually quoted Psalm 150 (among other misapplied Scriptures, e.g. 1 Corinthians 14, 1-33) to support them. There were in my (currently former) parish some people, among whom a choir director who led an excellent liturgical choir, who on a few occasions attempted to argue with me and the other young people who directed a youth choir following our (wrong) ideas about liturgy. Unfortunately, they consistently adopted an aggressive, know-it-all attitude. To change my mind, I had not only to realise that my arguments were wrong and theirs were right, but I also had to see that the fact that the other side was being arrogant did not prove their arguments wrong. This difficulty, of course, was not intellectual: I knew all along that arrogant people can be right (and just should support their correct views otherwise); the difficulty (at least in my case) was mostly sentimental, and thus harder to overcome. My dislike for the attitude of those who supported chant and polyphony and quoted Church documents was a weighty obstacle for me to realise that, in spite of them, their ideas were right.

Two final notes. Firstly, I also realised that my own attitude had all along been also arrogant: I saw that I thought that, even though I knew far less than they did about music, liturgy, etc., what I knew was more than enough, and they, for all their knowledge, were stuck with old-fashioned, unchristian ideas, etc. This is because knowing too much can make someone arrogant, and that is a real danger, but ignorance can also lead to arrogance; it is the sort of sin that seems to threaten all people alike, just in different manners. Secondly, this arrogance of mine does have some tendency to resurface when I am now asked to support my views (often by people who knew I once adamantly defended contrary ones). I just hope that my experience of having been kept away from Sacred Music for a while also because of the attitude of those who promoted it may help me avoid the same fatal error when I now make its defence. And I strongly advise all those who fight for Sacred Music never to do it with feigned superiority.