The demons knew exactly who Jesus was, and they were afraid. Their first question pushes Him away. Barnes says it could be read, "What hast thou to do with us?" and means, "Why dost thou trouble or disturb us?" Matthew Henry says, "The devils have nothing to do with Christ as a Saviour; they neither have, nor hope for any benefit from him." Gill adds, "but he had to do with them, and that was what they dreaded." Their second question reveals what they feared most. Barnes explains, "By 'the time' here mentioned is meant the day of judgment." They knew a day of torment was coming, and they were afraid it had come early.

Jesus did not answer their questions with words. The devils begged, "If thou cast us out, suffer us to go away into the herd of swine," and Jesus said one word: "Go" (Matthew 8:31-32). The whole herd "ran violently down a steep place into the sea, and perished in the waters." The keepers fled to the city, and then "the whole city came out to meet Jesus" and "besought him that he would depart out of their coasts" (Matthew 8:33-34).

"What have we to do with thee" is in Greek ti hēmin kai soi, literally "What to us and to you?" "Torment" is basanizō. Thayer says it meant "properly, to test (metals) by the touchstone," and then came to mean to torture or torment. The Textus Receptus, the Greek text behind the KJV, includes the name "Jesus" in this verse; other Greek texts do not, which is why the ESV reads only "O Son of God."

Mark and Luke call the place "the country of the Gadarenes" and focus on one man (Mark 5:1-2; Luke 8:26-27). Gill explains that Gergesa and Gadara were two cities "near each other, in the same country," and the region could be named after either. Barnes notes that Mark and Luke do not say there was only one man.

This question shows the authority of Jesus over every evil power. The demons speak first, but they speak as prisoners pleading with a judge. They must ask His permission even to go into the swine, and at His word "Go," they leave (Matthew 8:31-32). Matthew Henry writes, "Satan and his instruments can go no further than he permits; they must quit possession when he commands."

It also completes the question the disciples had just asked: "What manner of man is this?" (Matthew 8:27). The demons answer it: "thou Son of God." Yet knowing who Jesus is did not save them. Matthew Henry says their torment was "to be forced to own the excellence that is in Christ," with no part in Him. Sadly, the people of the city also asked Jesus to leave, after the keepers told what had befallen the possessed men (Matthew 8:33-34).