Answer

There is no formal commandment in this. Of course, protecting lives is a commandment, just like someone who protects people’s lives in Australia. By the way, among the obligatory wars in Maimonides, one of them is coming to Israel’s aid against an enemy. Many think that this is an actual commandment, but in my opinion it is different from the other two. The others are a specific commandment, whereas this one is only the protection of life.