John Chrysostom — as excerpted in the Catena Aurea on Matthew 10:16-18

“(Hom. xxxiii.) Having removed all care and anxiety from the Apostles, and armed them with the miraculous powers, He proceeds to foretell the evils which should befal them. First, that they might know his knowledge of the future; secondly, that they should not think that these things befel them because of the want of power in their Master; thirdly, that they might not be amazed if these things had come upon them unexpectedly; fourthly, that after hearing these things, they might not be dismayed in the season of His cross; and lastly, that they might learn a new method of warfare. He sends them unprovided, bidding them look to those who should receive them for support; but rests not in that, but shews his power still further, Lo, I send you as sheep in the midst of wolves. Where observe that He does not say merely ‘to wolves,’ but in the midst of wolves, to shew His excellent might therein, that the sheep would overcome the wolves though they were in the midst of them; and though they received many bites from them, yet were they not destroyed, but rather convert them. And it is a much greater and a more wonderful power that can change their hearts than that can kill them. Among wolves He teaches them to shew the meekness of sheep.”