Q: Context: "The pot calling the kettle black" is a proverbial idiom that seems to be of Spanish origin, versions of which began to appear in English in the first half of the 17th century. It is glossed in the original sources as being used of a person who is guilty of the very thing of which they accuse another and is thus an example of psychological projection.

Question: where does the saying calling the kettle black come from? Let's give stream of consciousness first:
The relevant information to answer the above question is: "The pot calling the kettle black" is a proverbial idiom that seems to be of Spanish origin, versions of which began to appear in English in the first half of the 17th century. Therefore, the final answer is seems to be of Spanish origin , versions of which began to appear in English in the first half of the 17th century.