The honorable Rev. FSSL said:
See this article... written by a lawyer, not a theologian
http://blog.discoverworship.com/articles/the-case-for-importance-of-church-choir
For a long time English Baptists didn't even sing. It all started when they were hiding from persecutors in England - if they sang they would have been discovered. It eventually became a habit and even forbidden when they had some liberty. I bet they understood "Singing with grace in your hearts" better than anyone. Choirs are great but essential? No. Grace in your heart is essential. Being Spirit filled is essential.