Thus, faith in Christ leads to righteous action, which increases our spiritual capacity and power. Understanding that faith is a principle of action and of power inspires us to exercise our moral agency in compliance with gospel truth, invites the redeeming and strengthening powers of the Savior’s Atonement into our lives, and enlarges the power within us whereby we are agents unto ourselves (see D&C 58:28).

Source: “Ask in Faith,” Ensign, May 2008, p. 95