"Men are free according to the flesh; and all things are given them which are expedient unto man. And they are free to choose liberty and eternal life, through the great Mediator of all men, or to choose captivity and death, according to the captivity and power of the devil."
Agency is freedom of the soul, the unfettered right to choose. It is essential to the plan of salvation. Righteousness cannot be forced because, as Lehi taught, if there is no opportunity for wickedness, there can be no opportunity for righteousness (2 Nephi 10:23). What could righteousness possibly mean if it were forced upon us? The attributes of godliness are developed only when coupled with the ability to choose. The Savior's redeeming sacrifice grants us the opportunity for eternal life—but only if we choose to follow him. The righteous followers of Christ cleave unto that which is "honest, true, chaste, benevolent...virtuous, lovely, or of good report or praiseworthy" (Article of Faith 13); whereas the companions of evil seek for that which is foolish, false, carnal, sensual, and devilish. That which is of Satan debases. That which is of God exalts and purifies. This is the day to freely and wholly choose the Lord and his righteousness.
— When Ye Shall Receive These Things, p. 89