Adam Clarke's Commentary on the Bible - 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, Matthew 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... read more
Adam Clarke's Commentary on the Bible - Luke 10:18
I beheld Satan - Or, Satan himself, τον Σαταναν , the very Satan, the supreme adversary, falling as lightning, with the utmost suddenness, as a flash of lightning falls from the clouds, and at the same time in the most observable manner. The fall was both very sudden and very apparent. Thus should the fall of the corrupt Jewish state be, and thus was the fall of idolatry in the Gentile world. read more