When we are inclined to take matters into our own hands, the Psalms teach us to trust God. When we would insulate ourselves from pain, they teach us to trust God. Instead of vowing that we will never again move close to another person, we learn to trust God. Instead of extinguishing hope, the Psalms teach us to trust God and, as a result, be filled with jubilant expectations for the coming of the kingdom. You could say that the Psalms improve our quality of life.
