The pot calling the kettle black

The pot calling the kettle black is an idiom describing the act of a person criticizing another person for a fault that the speaker is himself guilty of. The saying is generally used in the form of private grumbling among people who have been criticized over something. "Can you believe what he said? That's a real case of the pot calling the kettle black."

In colonial days, cooking was done with pots suspended over the fire in the fireplace, and those pots became black from soot and oxidation. No piece of cookware would be justified in criticizing another piece of cookware over this.

Examples of this behavior abound in everyday life. One of the best-known public examples of this might be the Katyn massacre during World War II. The Soviet Union and Nazi Germany, each blamed the other for it, despite their own monstrous human rights records.

In fact, this kind of behavior is so commonplace that it was criticized (not in those words, of course) by Jesus in the Sermon on the Mount:

“	And why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye?	”
—Matt. 7:3, KJV

Because this saying carries the implicit notion that "black" is equated with "bad", some people who have a good sense of humor over issues of political correctness have jokingly suggested that the racial overtones could be overcome by using the phrase "the maggot calling the pus white".