Elk by the River is a poem written by Wang Zhihuan, a poet in the Tang Dynasty. It describes that the elk by the river depended on their owners' pets, took pride in their "inner dogs" and were finally killed by "outer dogs". It means that people should have self-knowledge, be good at distinguishing between right and wrong and the enemy, be arrogant because of favoritism, and mistakenly regard others' partiality as their own talent, which will easily lead to self-destruction.
The full text satirizes those "slaves who flatter their masters" who have no self-knowledge and rely on their masters' power to survive, expresses the author's satire on those who relied on their powers at that time and points out their doomed fate.