Living a sacrificial life equates to the highest degrees of happiness and contentment possible.
Also Jesus said [paraphrased] there is no greater love than this that one should lay down his life to spare the life of a friend or a loved one.
Let me paraphrase Patton. The goal is not for you to die for your country, the goal is for you to make the other guy die for his country.
Real Christians knew that simple truth. That is why they blessed the bombs, planes and ships that went out to war.