it takes one to know one

In the it-takes-one-to-know-one category. Lester L. Kinsolving, among other jobs, is serving as national editor for the Panax Corp. newspapers.
[1977 National Journal 9 July 1090]

We hear that a local dude discourages his wife from buying antiques by saying, ‘It takes one to know one.’
[1997 Buffalo News 27 Aug. 9D]

‘Sam just wasn't the suicidal type.’ ‘Takes a one to know a one, does it?’ said Dalziel.
[2001 R. Hill Dialogues of Dead xxiii. 200]

Related to: similarity and dissimilarity

Bibliography of major proverb collections and works cited from modern editions is available here.

The person who expressed criticism has similar faults to the person being criticized. This classic retort to an insult dates from the early 1900s. For example, You say she's a terrible cook? It takes one to know one! For a synonym, see pot calling the kettle black. A near equivalent is the proverbial it takes a thief to catch a thief, meaning "no one is better at finding a wrongdoer than another wrongdoer." First recorded in 1665, it remains current.