Sacrifice is usually one of the hardest, though most important things you can do. It means putting someone else's needs before your own. I get my sense of sacrifice from my parents. Growing up during The Great Depression, they made sacrifices unfathomable to most of us living today. Those sacrifices continued in their desire to give the best opportunities to their children - no doubt an effort to best equip us to succeed and overcome hardship in our lives. My parents are now deceased but their example of sacrifice has been a vital component in my own approach to living life. I know I can do better though - like I said, sacrifice isn't always easy.
Of course, sacrifice extends beyond your own family. There is an equally important societal obligation. That aspect became clearer to me as I reached middle age. Basically, it's the old adage of "you reap what you sow." As a society we're in difficult times right now. It's important to find a way to contribute positively to the lives around us. It goes beyond just not being selfish - it means going that extra step. It might mean devoting time, money, or whatever to improving someone else's fortunes but certainly, it will involve personal sacrifice.