Let me continue my thoughts on the trinitarian re-enchantment of the world, miracles and the demonic with some notes -- I'm sure these will be more scattered! -- on the Satan.
Throughout the Bible, the satan is portrayed as being a creature ordained and directed by God, fulfilling his function of being an adversary. In fact, the Hebrew word satan means "adversary", and in its earlier usage it carries the definite article ("the satan", or "the adversary"). Satan is portrayed as a courtroom prosecutor, and God is the judge; Satan looks for evidence against God's people (e.g. Job 1-2), and God even lets him use entrapment and sting operations. Over time, however, the portrayal of Satan shifts from being God's servant to being God's enemy, as Satan takes his efforts to accuse God's people further, breaking the boundaries that God puts on him (think for example of Daniel 10). By the time we get to the NT, Satan is God's enemy, yet unwittingly or unwillingly continues to serve God's purposes by doing what he always does: Entrapping and accusing people.
When I think of "the Satan", I first think of God's servant, someone ultimately answerable and beholden to God as an inferior, most certainly not an equal. Satan's "fall", then, is disobedience -- going outside of the boundaries that God had placed upon his accusations and adversity. This is a pattern for all of the fallen powers: They continue to do what they were created to do, but they do it deficiently and for their own purposes and glory. They're like a banker who starts to siphon funds, or a politician who uses his influence to pad his own pockets or accept bribes; they still have the same job, and they do it to some extent, but they do it for themselves rather than for their true master. In a word: Idolatry.
Idolatry, I think, is the reversal of the Creator-creature relationship (Romans 1-2). In it, the creature demands the service of the Creator. This is certainly true of actual, physical idols: A human being makes a statue of gold, and then bows down to worship it, leaves food out for it, etc. This is true of the love of money: Money is a tool for our good, but we spend all of our time and energy trying to get more of it, to the point where we're serving it rather than the other way around.
All sin has some form of idolatry in it -- not least the sins of the Powers, who were created by God to serve humanity but have instead demanded service from us, setting themselves up in the place of God. Governments are set up to protect their people, but they start foolish wars and millions are killed; economies are set up to circulate money and increase wealth, but they set up monopolies to hoard the wealth and enslave the people with consumerism; even marriage, perhaps the institution most celebrated as being Christian, is a fallen Power as often as not, with people looking for need fulfilment and impossible romance in a relationship that can't actually provide such levels of service. For the amount that we spend on books, magazines, and lawyers, all telling us how to have a healthy/happy marriage/divorce, or how much we spend on a wedding with all of the social trappings that come along with it, it's clear that, at least at times, we're serving the institution of marriage more than it's serving us (or from another perspective, perhaps we're expecting service from our marriages when we should actually be the ones serving?). Nothing is sacred, nothing is exempt -- all of the Powers are fallen to some extent or another, and we have our fingers in it.
That little excursion actually helps in setting up what I think about Satan. Over time, Satan accrues more and more names: Adversary, yes, but also Accuser, Slanderer, and Destruction, among others. He gets worse, more powerful, more hateful and spiteful -- at least that's how he's portrayed.
Part of the tension found throughout the Bible when the topic of Satan is mentioned comes from the ambiguity of whether or not Satan is a real spiritual being of evil nature, or if he is merely a personification of the human adversaries that are faced by the community creating the texts. As the Church emerges and faces opposition, they aren't afraid to call their adversaries, human or otherwise, Satan! That some scholars see the term referring to a personification or demonization of the Church's enemies rather than a real personal demon is rather interesting; I take it a step further.
Satan is not just a name to call one's enemies, but is the personification of all of the powers combined: As Walter Wink puts it, "The Domination System". Rather than being a spirit in the sky who can deal out plagues and earthquakes and bad luck, or possess people and make them do evil things, Satan is the literary personification of the entire Domination System, which itself is made up of all of the fallen powers of this world. Individual fallen powers are bad enough, but when they act in concert, it's pure and utter domination.
Take, for example, sweatshops in the third world: This is a failure of so many different social institutions around the world! Complicit in the atrocity that is sweatshop labor are the powers of economy (ours, which depends on cheap goods produced in sweat shops, and theirs, which depends on low-wage work that keeps their people in poverty rather than enriching them); government (ours, which should hold our corporations responsible for what they do overseas, and theirs for not protecting their people adequately); culture (ours, for being materialistic and colonialist, and cultures around the world for attempting to imitate ours, often in the worst ways); religion (for failing to speak up, both here and there); and many others.
Any one alone is bad. Together, they embody a System that dominates and shrinks human life. Together, they dehumanize and deface the image of God in which we're made.
One of these systems going wrong is adversity -- the thing that God allows Satan to bring on us, the thing that helps us to grow and work together for good; all of these systems going wrong at once is domination, is Satan pushing us past any sense of growth in adversity, to the point of utter desolation. Job, we could say, was pushed that far -- yes, that's true; but Job is supposed to be an extreme case, a hyperbole for the sake of the story and its point, not a depiction of the way things are supposed to be.
So, once again, I'm denying the existence of a disembodied supreme malevolent spirit. I think that kind of dichotomous reading of the biblical witness is a misreading.
Instead, I think the Satan is a very real, very physical manifestation of fallen Power. Satan is the supreme embodiment of all those powers and principalities working together in adversarial threat of human life.
Is the Satan a personal spiritual force? Practically speaking it doesn’t actually matter, because personal or not, it's still social and spiritual. Is the Satan working for God or in rebellion against God? Once again, practically speaking it doesn't matter -- because God uses its actions for our good, regardless of their intent; and on the flipside, whether God sent Satan to do these things to us, or whether Satan does them out of an idolatrous self-motivation, it's still adversity that we need to grow through together, and we still have a role to play in how these issues are resolved.