Adam Clarke on Luke 10:19

To tread on serpents, etc. - It is possible that by serpents and scorpions our Lord means the scribes and Pharisees, whom he calls serpents and a brood of vipers, Mat 23:33, (see the note there), because, through the subtilty and venom of the old serpent, the devil, they opposed him and his doctrine; and, by trampling on these, it is likely that he means, they should get a complete victory over such: as it was an ancient custom to trample on the kings and generals who had been taken in battle, to signify the complete conquest which had been gained over them. See Jos 10:24. See also Rom 16:20. See the notes on Mar 16:17, Mar 16:18.