Answers to Gospel Questions 1:32; “The means provided for our redemption from death were prepared in the plan of salvation before Adam and Eve were sent to the earth, and Jesus Christ volunteered to come and atone for this transgression and thus gain the victory over the devil.”
Revelation 13:8; “And all that dwell upon the earth shall worship him, whose names are not written in the book of life of the Lamb slain from the foundation of the world.”
This teaching of Adam having to sin is called “dualism”. It means that there are two independent divine beings or eternal principles, one evil and the other good. (See dictionary.com) Mormonism embraces this theory as do witches and Satanism.