Elder Quentin L Cook, Personal Peace: The Reward for Righteousness, April 2013 General Conference

Agency is essential to the plan of happiness. It allows for the love, sacrifice, personal growth, and experience necessary for our eternal progression. This agency also allows for all the pain and suffering we experience in mortality, even when caused by things we do not understand and the devastating evil choices of others. The very War in Heaven was waged over our moral agency and is essential to understanding the Savior’s earthly ministry.