Fig.: criticizing someone for faults that one has oneself

You say my desk is messy?! That's really the pot calling the kettle black. Look at your desk: it's so full of junk that there is no room left, not even for a pen

Dici che la mia scrivania è un casino?! Da che pulpito viene la predica! La tua è talmente piena di scartoffie che non c'è posto nemmeno per una penn

You are accusing me of spending too much? Well, talk about the pot calling the kettle black! When you enter a store you never ever come out empty handed

E tu mi accusi di spendere troppo? Da che pulpito! Ma se quando entri in un negozio non esci mai, dico mai, a mani vuote…

Up to the end of the 19th century, more often than not, pots and kettles were made of iron, then were black coated with oxide and were further blackened by soot from the wood fires used for cooking. The source of the expression is probably Cervantes' Don Quixote, with the simple sentence “The pot calls the kettle black”