[This is a comment I made elsewhere that seemed too important not to post.]
(Acts 21:26) The next day Paul took the men and purified himself along with them. Then he went to the temple to give notice of the date when the days of purification would end and the offering would be made for each of them.
He was arrested before he could actually make the sacrifice, but his intentions were clear — he went to worship at the temple. And the temple was filled with instrumental worship of God!
According to the Mishna, the regular Temple orchestra consisted of twelve instruments, and the choir of twelve male singers.
Just so, the early church met at the temple –
(Acts 2:46) Every day they continued to meet together in the temple courts. They broke bread in their homes and ate together with glad and sincere hearts,
where instrumental worship was taking place.
And, evidently, the early Jewish Christians continued to participate in the temple worship –
(Acts 3:1) One day Peter and John were going up to the temple at the time of prayer – at three in the afternoon.
(Acts 21:20-24) When they heard this, they praised God. Then they said to Paul: “You see, brother, how many thousands of Jews have believed, and all of them are zealous for the law. 21 They have been informed that you teach all the Jews who live among the Gentiles to turn away from Moses, telling them not to circumcise their children or live according to our customs. 22 What shall we do? They will certainly hear that you have come, 23 so do what we tell you. There are four men with us who have made a vow. 24 Take these men, join in their purification rites and pay their expenses, so that they can have their heads shaved. Then everybody will know there is no truth in these reports about you, but that you yourself are living in obedience to the law.”
It seems obvious from the passage in c. 21 especially that the Jewish Christians in Jerusalem continued participating in temple worship — which included instrumental music!
Paul did not condemn them. Nor did the the apostles who remained in Jerusalem. Indeed, Paul was preparing to join them!
One could argue, with the rabbis (but without scriptural support) that instrumental music is solely for temple worship. But today the assembled congregation is the new temple! (1 Cor 3:16-17; Eph 2:21-22; cf 1 Cor 9:13).
Now, the fact that the apostles saw nothing wrong with participating in worship that involved instrumental music has to have some bearing on the issue. I mean, if the argument is that instrumental music is wrong for all the reasons suggested by early uninspired Christians — it leads to animalistic emotions, it’s too Jewish, it’s too pagan, it lacks a message — why weren’t those same objections true when the earliest Christians went to the temple to worship?