Amongst all his brothers with earth shattering spears held high, no arms shall be taken up.
Amongst all his brothers - There's quite a few of these little things. SOMEONE GET A SUPER SCOPE 6!! j/k!!;D
with earth shattering spears held high - They're wearing mining helmets and holding shovels. A shovel is kinda like a spear, except it's designed to break up and pull apart the ground, or in another word, shatter.
no arms shall be taken up. - These little guys are peaceful critters. To take up arms against something means to fight, or more literally, use weapons against. They aren't using their shovel for anything other than digging, and they don't fight you or anyone else anyway.