1 Cor. 15:29
The basic question of authority must first be settled with Mormons as with Roman Catholics. While it is claimed by Mormons that the Bible is the word of God, the claim has little practical value since the real stress is placed on the later "revelations". A Mormon course of study for the Melchizedek priesthood gives the following instruction:
It is not usually advisable to condemn Mormon books outright on the basis of Rev. 22:18, "If any man shall add unto these things, God shall add unto him the plagues that are written in this book". Mormons interpret this verse as only applying to the Revelation. Their stock rejoinder is to quote Deut. 4:2, "Ye shall not add unto the word which I command you, neither shall ye diminish ought from it . . . " They then ask whether or not the later writings of Joshua, Judges, the Prophets and the New Testament are accepted as inspired revelations.
A more fruitful approach utilizes the small common ground that a Christadelphian shares with a Mormon - the belief that the Bible is the Word of God. The Bible can then be used to test the claims of the Book of Mormon, the Doctrines and Covenants, and the Pearl of Great Price. This approach has the advantage of discussing the basic issues of Gospel doctrines rather than disputing for example, whether or not the Indians of the Americas could have used steel swords.2 The Christadelphian argues on his strong familiar territory, not on historical and anthropological details. Arguments about the latter inevitably degenerate into a battle of "authorities" with each citing what the "scholars" say.