The pot calling the kettle black - 五十步笑百步 wǔshí bùxiàobǎibù

 

I was really pleased to find this Chengyu 成语 chéngyǔ.

五十步笑百步 --  wǔshí bù xiào bǎibù -- The pot calling the kettle black.  a literal translation "those who retreat 50 steps laugh at those who retreat 100 steps"

The phrase "The pot calling the kettle black" is an idiom used to claim that a person is guilty of the very thing of which they accuse another. Wikipedia