John Gill Commentary Matthew 8:29

"And behold, they cried out, saying, What have we to do with thee, thou Son of God? art thou come hither to torment us before the time?" — Matthew 8:29 (ASV)

And behold they cried out, saying This is an instance and proof of the wonderful power of Christ over the devils; and has therefore the note of admiration, "behold!" prefixed to it, that the devils themselves who had taken possession of these men, and made them so fierce and cruel, and outrageous, that there was no passing the way for them; yet upon the sight of Christ, and especially at hearing his orders to come out from them, not only say, but cry out, as being in great consternation, horror, and fear, and with the utmost subjection to him,

what have we to do with thee, Jesus, you Son of God ? They had nothing indeed to do with him; they had no interest in his grace, blood, righteousness, and salvation; he was no Saviour for them. But he had to do with them, and that was what they dreaded. Therefore, they mean that he would let them alone, in the quiet possession of these men, and not disturb and dislodge them; for they knew that he was Jesus, the Saviour of sinful men (though none of theirs), the true Messiah. They knew also that he was "the Son of God", a divine person, possessed of almighty power, and so an overmatch for them. At his presence they trembled, and his all commanding voice they were obliged to obey, though sorely against their wills.

Are you come here to torment us before the time ? This question implies the apprehension the devils had of Christ as a judge, and their sense of his authority and power to punish them. They also sensed that they deserved it and expected it, nor do they say anything against it. They only imagine that the time of their full torment was not yet come, which is generally referred to the day of judgment, to which they were reserved by the appointment of God. They had some notion of this and saw it as at a distance. Therefore, they complain of Christ's coming to them now and expostulate with him about it:

though it may be understood of the time they had proposed to themselves to abide in the men they had possessed, and which they concluded they had a permission for. Nothing could give more torment, pain, and uneasiness than to be turned out, remanded to their prison, and restrained from doing more mischief to the bodies and souls of men.

Or whether this may not have some respect to the time of the preaching of the Gospel and setting up the kingdom of Christ among the Gentiles, of which the devils might have some hint as not yet to be, I leave to be considered. This is with the observation: that there seems to be a considerable "emphasis" on the word "hither," meaning the country of the Gergesenes, a Heathen country, at least where many Gentiles inhabited. It is as if they had said, is it not enough that you turn us out of the land of Judea and have dispossessed us out of the bodies of men dwelling there? But you pursue us here also and will not let us have any rest, even in this Heathenish land, though the time is not yet come for the dissolution of our empire and government in the Gentile world?