To greet s.o.
At nighttime when one cannot see who is calling at the door or passing on the road one asks ‘who are you?’ rather than greeting him. The answer will usually be ‘it is I’. If one does not recognize the voice one may ask ‘I who?’.
When they arrived there they were greeted by the sultan.
That person does not even greet.
He told me to greet people when they arrive.