[pot call the kettle black] {informal} The person who is criticizing someone else is as guilty as the person he accuses; the charge is as true of the person who makes it as of the one he makes it against.
* /When the commissioner accused the road builder of bribery, the contractor said the pot was calling the kettle black./* /Bill said John was cheating at a game but John replied that the pot was calling the kettle black./