John Gill

But he said unto them,.... That is, "Jesus", as the Persic, or the Lord Jesus, as the Ethiopic versions express it: I have meat to eat that ye know not of: meaning the conversion of the Samaritan woman, and of other Samaritans, who were flocking in great numbers to him, which he knew, though his disciples did not; and the harvest of souls he had a prospect of, see Joh 4:35, was as meat unto him, delightful and refreshing; and his mind and thoughts were so taken up with these things, that he had no inclination to any corporeal food.