Investigators say the two men got into an argument as a southbound 2 train approached the Sterling Street subway station in Prospect Lefferts Gardens on Sunday.
That's when the suspect stabbed the victim in the head and torso and then fled the scene.
The victim was taken to Kings County Hospital and is expected to recover.
Anyone with information is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782).
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Brooklyn bishop robbed at gunpoint in the middle of church service
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