like minds gather; birds of a feather flock together
A classical idiomatic expression meaning that people with similar interests or temperaments naturally come together. Rare in modern conversation; more common in literary or proverbial contexts.
The phrase '同気相求める' is an old expression meaning that like attracts like.
A more common modern proverb with the same meaning; '同気相求める' is its classical, less frequently used counterpart.
From the 易経 passage 同声相応、同気相求, “like sounds answer one another, and like energies seek one another.”