I'm curious about the Jewish approach to war and I've been trying to find information on whether Jews refrain from fighting on the Sabbath. I can't find a resource online that directly addresses the question, but this passage from the Bible touches on the issue:
2 Kings 11:4-8Standing guard is apparently ok on the Sabbath, and that's essentially a defensive military action.
In the seventh year Jehoiada sent for the commanders of units of a hundred, the Carites and the guards and had them brought to him at the temple of the LORD . He made a covenant with them and put them under oath at the temple of the LORD . Then he showed them the king's son. He commanded them, saying, "This is what you are to do: You who are in the three companies that are going on duty on the Sabbath-a third of you guarding the royal palace, a third at the Sur Gate, and a third at the gate behind the guard, who take turns guarding the temple- and you who are in the other two companies that normally go off Sabbath duty are all to guard the temple for the king. Station yourselves around the king, each man with his weapon in his hand. Anyone who approaches your ranks must be put to death. Stay close to the king wherever he goes."