A.T. Robertson Commentary Luke 4:27

"And there were many lepers in Israel in the time of Elisha the prophet; and none of them was cleansed, but only Naaman the Syrian." — Luke 4:27 (ASV)

In the time of Elisha the prophet (επ Ελισαιου του προφητου). This use of επ with the genitive for "in the time of" is a good Greek idiom. The second illustration of the proverb is from the time of Elisha and is another heathen,

Naaman the Syrian (Ναιμαν ο Σψρος). He was the lone leper that was cleansed by Elisha (2 Kings 5:1,14).