A poem in an early-twentieth-century school textbook runs:

"Oho!" said the pot to the kettle; "You are dirty and ugly and black! Sure no one would think you were metal, Except when you're given a crack." "Not so! not so!" kettle said to the pot; "'Tis your own dirty image you see; For I am so clean – without blemish or blot – That your blackness is mirrored in me."

—Maxwell's Elementary Grammar, 1904

The phrase is much older than that:

One of the earliest written instances of the phrase appears in Don Quixote, by Cervantes. The epic book was published in the early 1600s, and had a big influence on the English language. Numerous terms and idioms have their roots in Don Quixote, such as “quixotic” to describe an idealist. Shakespeare also played with the concept in one of his plays, as did many of his contemporaries. The phrase has been twisted and expanded over the centuries, appearing in forms like “pot, meet kettle.”

Some people believe that the phrase is racist, since it refers to the surface color of the objects involved. These individuals might want to keep in mind that in a modern kitchen, the idiom might be “the pot calling the kettle silver,” in a reference to the fact that many modern pots and kettles are often made from polished stainless steel. In this particular instance, skin color has nothing to do with the idiom, except in the sense that both of the objects involved are the same color.

Yes, I love the pic you added.  I just shared that quote because it was so cute and so illustrative!  Thanks!

You are very welcome Tina!