Article 21.
We are opposed to war. Men are not justified in taking up arms against their fellows except as a last resort in defense of their lives and to preserve their liberty.
Self defense is the only reason to take up arms against other people. We should not look for war. All life is a gift from God and we should not kill people lightly. We do have to the ability to defend both our lives and our freedom. God wants his people to live in peace. For further study read James 4:1-3 and Alma 60:29
