The prologue in Iraq – featured in both Blatty’s (R.I.P.) novel and Friedkin’s film – connects with the rest of the story because it introduces the viewer, from the first frame, to the theme of “the Demonic”, and to “the exorcist”, Fr. Lankester Merrin.
Merrin’s ongoing fearful reaction to the stone Pazuzu amulet, and the large Pazuzu statue on the hill, describe his inner state. Since they convey and produce fear, we immediately know that there is “something special” that accrues to them – something which is evil. The museum curator acknowledges this when he says of the amulet, “evil against evil”. As a Muslim, he probably believes that Paganism and its charms and idols are evil. But Merrin – as the story will tell us – is familiar with an even more universal evil, namely a demon he expelled some twelve years earlier.
The sense of evil and omen is not limited to the statuary at the dig. It is present in the over-loud street noises as Merrin takes tea; in staring Arabs; in the nitro that we see him taking. He is old and has a bad heart. When the clock stops in the curator’s office, it means more than a classic paranormal event presaging death: in a real sense, it hints at the stopping of Merrin’s own “ticker”, which happens at the story’s climax.
Merrin also runs across evil in the form of human weakness and illness: he sees an Iraqi leading a blind or lame partner by the hand; then he encounters a blacksmith afflicted with blindness in one eye.
The omens and premonitions continue: along his way he is nearly run over by a droshky whose passenger is an old, sick-looking woman. Just before this, we see that he is being watched by a silent man in a tower. Omens and premonitions.
What had started as a standard archeological dig has now become a projection-carrier for Merrin’s fears, specifically as the novel says, in the certainty that “soon he would face an ancient enemy”. The very air of Iraq itself now reminds Merrin of the kinds of feelings he had in the African exorcism twelve years before. The atmosphere has become, in Jungian terms, a projection carrier for the elderly cleric.
Finally, the old priest confronts the Pazuzu statue, but not without first encountering rifle-toting guards. As he ascends the hill, the camera shows a single Arab staring at Merrin, while the soundtrack presents the sound of tumbling rocks (will Merrin “loose his footing”?).
Then, as he faces the Pazuzu statue by the light of the setting sun, a demonic wind whips up to the tune of the frenzied growling of fighting dogs, while the soundtrack mixes a guttural “MERRIN!” into their cacophony.
That’s how Merrin and the Iraq prologue tie into the rest of the story. Once we see the old priest from the prologue walking in the American woods, and then arrive at the MacNeil house, we realize that the story is coming full circle and that now Merrin will indeed face “the ancient enemy”.
One misconception accrues to the prologue, namely, the notion that the archaeological dig somehow disturbed and released a sleeping or dormant demon. This explanation doesn’t really work, because the demon is not confined to any time and place – it is a non-material spirit entity not dependent on territorial or geographical roots. It is free to travel, to scrutinize potential victims, to go about the world in its own dark odyssey. Merrin first met it twelve years earlier in Africa – but who knows where it had been in earlier centuries and in different locales? Since its exorcism, it has been keeping tabs on Merrin, and Merrin, as the prologue shows, is psychically linked to the demon. He intuits its re-emergence into the world and into his life while he’s excavating.
But the excavation itself is not a causal element in Regan’s possession. The novel explains that the demon strongly desired a grudge match with Merrin because it did not like losing that time before, in Africa. It had finally located another target in the person of Regan MacNeil. Merrin sensed that something was brewing again, and went back to the States where he began working on another book, passing the time before the ultimate encounter. Events then conspire to convey the bishop’s message to Merrin, based on Damien Karras’s exorcism request. And we know how the story goes from there.