One Way by George Gillespie is a brief biblical argument for true uniformity flowing from the Scriptural principle of worship. He also rejects conforming to what is either against the Word of God or not required by it in matters of conscience. The Second Reformation in Scotland was marked by a desire to have as much harmony as possible in worship and church order. Gillespie expresses the views behind the desires of the Scottish Church for greater reformation during this period. It is such views and desires that brought about the documents produced by the Westminster Assembly.
It was prophesied of the church of the New Testament that God would give them one way as well as one heart, (Jeremiah 32:39). There would not only be one Lord but his name would be one in the New Testament period (Zechariah 14:9). We are exhorted to walk by the same rule as far as we have attained. This means to apply ourselves to uniformity not diversity in those things which are agreed upon to be good and right (Philippians 3:16).