What do the contemporary poskim say about the serving in the IDF? Do they consider it a Biblical commandment (mitzva de'orayta) if one chooses to serve?
I am obviously not talking about the controversial draft. But if a Jew by his own volition wanted to serve in the IDF does he fulfill a Mitzvah DeAroaita. I've heard certain mitzvot like Protecting the Land, or Pikuach Nefesh are cited, but I wanted to know if anyone has any sources from contemporary poskim.