'Mission' in the Bible

The LORD sent you on a mission: "Go and completely destroy the sinners, the Amalekites, and fight against them until they're destroyed.'

Saul told Samuel, "I did obey the LORD. I went on the mission on which the LORD sent me, I brought Agag king of Amalek, and I completely destroyed the Amalekites.

David answered the priest, saying to him, "Indeed, women were kept from us as is usual whenever I go out on a mission, and the equipment of the young men is consecrated even when it's an ordinary journey, so how much more is their equipment consecrated today?"

David told Ahimelech, "Is there no spear or sword available here? I took neither my sword nor my weapons with me, because the king's mission is urgent."