2 Nephi 2:2, emphasis added).
What this says to me is that because we have a Messiah, someone who has saved us from the consequences of evil if we will just let Him, we have the ability to act or to choose what we will do, say, and feel in any given situation. Situations and circumstances do not have the power to act upon us. We have the power to act upon them. Remembering that simple fact is empowering.
So when tempted to be less than you can be, shout out, "I choose good!" and then envision yourself doing whatever good you are contemplating and watch what happens. You have the power to Live in Truth every moment of every day!