Nine tents will be set up inside the cathedral. The crypt will also be used.
Workers already delivered 400 beds.
Patients are expected later this week or next.
It's unclear if the beds will be used for coronavirus patients or other patients to help alleviate strained hospitals around the city.
The Right Reverend Clifton Daniel III, Dean of the Cathedral said: "In the history and tradition of the Church, and following the example of Jesus, Cathedrals have long served as places of refuge and healing in times of plague and community crisis. The Cathedral of St. John the Divine is stepping up now, as we always have, to help support our diverse and beloved community and the community of doctors, nurses, and volunteers risking their health and well-being in the service of the people of New York City in our hour of need."'
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