A powerful and precise defense of the foundations of Reformation worship (and the regulative principle of worship) set in the context of Knox's refutation of the abominable idolatry of the Roman Catholic mass. The full printed version of this text is free at http://www.swrb.com/newslett/FREEBOOK/JKnox.htm .
This is a good teaching not only concerning the RCC Mass but also the Christ’s Mass which is the RCC Mass of Jesus’ birth also celebrated by Protestants and Evangelicals in their pagan/papist man-made worship which God hates.
If you prefer the video of this sermon: https://xmassh8trsblog.wordpress.com/videos/ohn-knox-true-and-false-worship-vindication-of-doctrine-that-sacrifice-of-the-mass-is-idolatry/
That God’s word damns your ceremonies, it is evident; for the plain and straight commandment of God is, “Not that thing which appears good in thy eyes, shalt thou do to the Lord thy God, but what the Lord thy God has commanded thee, that do thou: add nothing to it; diminish nothing from it.” Now unless that ye are able to prove that God has commanded your ceremonies, this his former commandment will damn both you and them.~John Knox’s History of the Reformation in Scotland