Matthew 10:16

All these verses relate to the sufferings of Christ's ministers in their work, which they are here taught to expect, and prepare for; they are directed also how to bear them, and how to go on with their work in the midst of them. This part of the sermon looks further than to their present mission; for we find not that they met with any great hardships or persecutions while Christ was with them, nor were they well able to bear them; but they are here forewarned of the troubles they should meet with, when after Christ's resurrection, their commission should be enlarged, and the kingdom of heaven, which was not at hand, should be actually set up; they dreamed of nothing then, but outward pomp and power; but Christ tells them, they must expect greater sufferings than they were yet called to; that they should then be made prisoners, when they expected to be made princes. It is good to be told what troubles we may hereafter meet with, that we may provide accordingly, and may not boast, as if we had put off the harness, when we are yet but girding it on. We have here intermixed, I. Predictions of trouble: and, II. Prescriptions of counsel and comfort, with reference to it. I.

— Matthew Henry's Concise Commentary (public domain)

Behold, I send you forth--The "I" here is emphatic, holding up Himself as the Fountain of the Gospel ministry, as He is also the Great Burden of it. as sheep--defenseless. in the midst of wolves--ready to make a prey of you (Joh 10:12). To be left exposed, as sheep to wolves, would have been startling enough; but that the sheep should be sent among the wolves would sound strange indeed. No wonder this announcement begins with the exclamation, "Behold." be ye therefore wise as serpents, and harmless as doves--Wonderful combination this! Alone, the wisdom of the serpent is mere cunning, and the harmlessness of the dove little better than weakness: but in combination, the wisdom of the serpent would save them from unnecessary exposure to danger; the harmlessness of the dove, from sinful expedients to escape it. In the apostolic age of Christianity, how harmoniously were these qualities displayed! Instead of the fanatical thirst for martyrdom, to which a later age gave birth, there was a manly combination of unflinching zeal and calm discretion, before which nothing was able to stand.

— Jamieson-Fausset-Brown Commentary (public domain)