The eagle is killed by the arrow made with its own feather.
The source for the proverb is Armenian Proverbs and Sayings by Kework Bayyan (1889). The image is by Harrison Weir at Flickr, an illustration of this Aesop's fable: An archer aimed at an eagle and let loose an arrow. The eagle was struck and as he turned and looked at the shaft which was tipped with his own feathers, he said, 'Many are betrayed by the very things that they themselves have wrought.' You can also find the same proverbial idea (abbreviated) in the title of Anton Myer's novel, Once an Eagle.
The poster is made with AutoMotivator.