Alma 52

It's important to note the difference between the purposes of the two armies. The Lamanites are seeking to take land that isn't theirs, to subject people and rule over them so that they can use them as slaves to support themselves and their way of life. The Nephites seek only to defend what is theirs, to maintain their liberty and their right to worship as they please. In battle, the Nephites slay only those who will not surrender their arms and promise not to fight. They try to avoid bloodshed in every possible way. Because the Nephites seek to have all of their actions be based on righteous principles, they are able to execute everything they do on a higher level, physically, emotionally and mentally. Their way of life enables them to be physically stronger. Emotionally, they have more confidence and faith in the purposes for which they fight, and their approach to life enables them to be mentally prepared in ways the Lamanites cannot contend with. So while a few battles may be lost, the war is won by the Nephites. It's the same way in our own lives. If we live righteously, we are able to physically, mentally, and emotionally deal with the challenges of life in a much more effective way. We may lose a few battles here and there along the way, but we will win the war. Knowing that makes it much easier to have more confidence in yourself and more assurance in the direction your life is taking.