You are probably in Kashuan Keep then trying to get the Egil Fire. Give Gordon a Shield and any weapon you can spare, he is not nearly as good as other characters in the game and if he dies, you may just let him be cause only some serious grinding will actually make him useful. Still if you can keep him alive it would be a good thing cause you have to use him again later.

The key here is to conserve your magic as much as possible and only use it when necessary against enemies like the Adamantoise or when you need to heal your health. Don't be afraid to try and run from battles as well because this dungeon can be brutal. If you are having serious issues, you can always head south of the Keep to find the game's only Chocobo Forest which you can use to get back to civilization to stock up on items and restore MP but that will also mean having to walk back to the Keep which is not very fun... I will still recommend using one bare handed fighter because as I mentioned earlier, they get vastly better damage pools than mid-game gear.