This is a great site to read awhile about worship.
It quotes the following excerpt from the Westminster Confession of Faith:
Regulative Principle in Worship
Westminster Confession of Faith
Of Religious Worship, [and the Sabbath Day]
I. The light of nature shows that there is a God, who has lordship and sovereignty over all, is good, and does good unto all, and is therefore to be feared, loved, praised, called upon, trusted in, and served, with all the heart, and with all the soul, and with all the might. But the acceptable way of worshipping the true God is instituted by Himself, and so limited by His own revealed will, that He may not be worshipped according to the imaginations and devices of men, or the suggestions of Satan, under any visible representation, or any other way not prescribed in the holy Scripture.