Adam Clarke on Acts 8:7

For unclean spirits, crying with loud voice, came out of many that were possessed - Hence it is evident that these unclean spirits were not a species of diseases; as they are here distinguished from the paralytic and the lame. There is nothing more certain than that the New Testament writers mean real diabolic possessions by the terms unclean spirits, devils, etc., which they use. It is absolute trifling to deny it. If we, in our superior sagacity can show that they were mistaken, that is quite a different matter!