Alma described a premortal spirit as "being left to choose good or evil" (Alma 13:3), and thus possessing the power to sin. The Savior's disciples believed that a person had power to sin in pre-mortality, as evidenced by their inquiry of the Savior, "Master, who did sin, this man, or his parents, that he was born blind?" (John 9:2). One-third of the premortal spirits committed such a serious sin in giving allegiance to Lucifer that they were cast out from the presence of God (D&C 29:36; Revelation 12:4). Peter explained that "God spared not the angels that sinned, but cast them down to hell" (2 Peter 2:4).... Joseph Fielding Smith Jr. so concluded: "The picture is complete. Man could sin before his mortal birth." (Religious Truths Defined, 94).


Tad R. Callister, The Infinite Atonement. 2000. p.76