Enright started up a conversation with Sharif, during which Sharif said he was Muslim. The following account comes from the cityroomblog of The New York Times.

After falling silent for a few minutes, the passenger began cursing and screaming, and then yelled, “Assalamu alaikum — consider this a checkpoint!” and slashed Mr. Sharif across the neck, and then on the face from his nose to his upper lip, the [New York Taxi Workers] alliance said.
…An emergency medical technician said that had the cut been any deeper or longer, the driver would have died, prosecutors said
…Mr. Enright sliced the driver’s “neck open halfway across his throat,” [said James Zaleta, an assistant district attorney]