He esteemeth iron as straw
You may as well cast a straw at him as a bar of iron; it will make no impression on his steeled back, which is as a coat of mail to him; so Eustathius affirms F4 that the sharpest iron is rebounded and blunted by him;
[and] brass as rotten wood;
or steel, any instrument made of it, though ever so strong or piercing.