Here is a beautiful song with a lot of kabbalistic meaning that I don't pretend to know. It has something to do with G-d having mercy on the jewish people when we fight our battles. In my mind this tune is associated with Hashem watching over the jewish people at times of war, especially with the most recent Gaza operation. But we say these words at various places in davening and particularly in Kabbalas Shabbos -welcoming the Shabbos Queen. I like the tune and Shabbos is coming. Enjoy!!!