Any army boys out there!?

My dad just left 2 weeks ago to do a year in iraq. he's been to afghanistan twice already and he said always remember ''rangers lead the way''. What does that mean? If anybody in iraq knows master sergeant sandros tell him his daughters Lindie, Cindy, and his wife Mindy said they cant wait for him to come home and he should be getting letters anyday now. He shoots big cannons so look for him in that section please