"Here am I. Send me!" ~ Isaiah 6:8.
It's an attitude thing. Some say it's a calling and some disagree.
Some say it has to be religious but I'm not so sure. I tend to think it's a personal choice thing. Some volunteer for stuff and some don't. Many years ago I was lucky enough to be a 'triple volunteer' and I guess that formed my thinking about those who volunteer a little bit. I'm not just talking military though. I'm talking about any kind of service here. I'm talking about anyone who raises their hand and volunteers to do stuff. Whether selfless or selfish they step forward.
There's something about the volunteer who sings out "Send Me" that I love and respect enormously. If there is one quality that speaks to the best of us as human beings it surely must be ~ "Send Me".