An Eagle was soaring through the air when suddenly it heard
the whizz of an Arrow, and felt itself wounded to death. Slowly
it fluttered down to the earth, with its life-blood pouring out of
it. Looking down upon the Arrow with which it had been pierced,
it found that the shaft of the Arrow had been feathered with one
of its own plumes. "Alas!" it cried, as it died.

We often give people permission to make us feel the way we do. Letting someone do something to you only sends the message that it's ok to do it again. Until you're shot down, eaten up by ones own willingness to not stand up.

Often, one can give another the tools of their own destruction.