43 “When an unclean spirit goes out of a man, he goes through dry places, seeking rest, and finds none.
44 Then he says, ‘I will return to my house from which I came.’ And when he comes, he finds it empty, swept, and put in order.
45 Then he goes and takes with him seven other spirits more wicked than himself, and they enter and dwell there; and the last state of that man is worse than the first. So shall it also be with this wicked generation.”
My commentaries pretty much take one of two views of this passage. Gaebelein is typical of those who think “this wicked generation” refers to Israel in general and that the fulfillment of the Lord’s words will occur during the Tribulation.
Generation is certainly to be understood in the sense of race. The unclean spirit is idolatry. It had left the nation, and even now the nation is swept from that evil spirit and unoccupied, and boasts of reform. It will not be so forever. The unclean spirit will return and bring seven others with him and take possession of that house again, and the last condition, the end, becomes worse than the beginning. The return of the unclean spirit with its seven companions will take place during the great tribulation. — Gaebelein, pages 256-257.
Pentecost agrees that idolatry is the issue, but thinks the Lord’s words referred to the generation of Israel that was around when the Lord was on earth. I lean toward this view, because the true Israel will be saved during the tribulation, but I’m not certain.
As compared with the other nations of the world, Israel was like a house from which the demon of idolatry had gone out with all his attendants — really the “Beel-Zibbul” whom they dreaded. And then the house had been swept of all the foulness and uncleanness of idolatry, and garnished with all manner of Pharisaic adornments. Yet all this while the house was left empty; God was not there; the Stronger One, Who alone could have resisted the Strong One, held not rule in it. And so the demon returned to it again, to find the house whence he had come out, swept and garnished indeed — but also empty and defenseless. The folly of Israel lay in this, that they thought of only one demon — him of idolatry — Beel-Zibbul, with all his foulness. That was all very repulsive, and they had carefully removed it. But they knew that demons were only manifestations of demoniac power, and that there was a kingdom of evil. So this house, swept of the foulness of heathenism and adorned with all the self-righteousness of Pharisaism, but empty of God, would only become a more suitable and more secure habitation of Satan; because, from its cleanness and beauty, his presence and rule there as an evil spirit would not be suspected. So, to continue the illustrative language of Christ, he came back “with seven other spirits more wicked than himself” — pride, self-righteousness, unbelief, and the like, the number seven being general — and thus the last state — Israel without the foulness of gross idolatry and garnished with all the adornments of Pharisaic devotion to the study and practice of the Law — was really worse than had been the first with all its open repulsiveness. — Pentecost, pages 209-210.