The Riddle of the Sword

Name that very keen contender which draws luster just like water from a stone, but which, unlike Alexander, does not owe it to a Khizr as a boon.

And which, like a tear-washed vision, purified by that ablution, is agleam, neat and clean and clear and limpid, with its raiment quite unwetted in midstream.

Its theme needs no longer statement than a single line, if trenchant.