A note on Matt. 12.43
"When the unclean spirit is gone out of a man, he walketh through dry places. Seeking rest, and findeth none. Then he saith, I will return unto my house from when I came out (Matt. 12. 43).
What is the meaning of "dry places"? Why should the dispossessed demon desire to avoid?
Jesus had in mind a very popular idea, to the effect that evil spirits shunned the crossing of water, and were unable to negotiate the passage of rivers or streams. This idea, so obviously absurd to us with our greater knowledge of the nature and powers of both holy and evil spirit beings, was a tradition, but very real to the people of our Lord's day. This verse is an interesting example of the fact that Jesus sometimes spoke to the people within the framework of the common thought of their own day—not that He himself necessarily endorsed these fables and legends, but used them in illustration of the truths He wished to inculcate. In referring to this popular idea of the evil spirit seeking a place of rest remote from the imaginary dangers of running water, He brought before his hearers the obvious sequel—that if the cleansed man's mind has been left empty and not occupied by the Spirit of God, the dispossessed demon would return from his wanderings, and settle down in the safety of his former home; and the last state of that man, said Jesus, would be worse than the first.
A homely illustration, built upon a Rabbinical fable having no basis in fact, but capable of teaching a vital spiritual truth. When the evil spirit is cast out, let the mind be filled with that which will prevent such a calamity as demon obsession ever befalling the man again.