I take it you are asking for critiques. If not, disregard the rest of this post.
A. What is good about it.
1. I like the use of multiple viewpoints. And you are doing it right--sticking to one viewpoint per chapter.
2. I like that you start with action, and start with the viewpoint character.
3. I like that you are using sensory details, telling us what the viewpoint character is experiencing, letting us see the story-world through the eyes of the viewpoint character.
4. I like that you are using stimulus & response, having characters feel, think, say, and act in response to things, rather than feeling, thinking, saying, or doing things spontaneously without explanation.
5. I like that you are writing in scenes, using dramatic exchanges.
6. I like that you used a transition between chapters 1 and 2. At the end of chapter 1, Gabriel decides to head for a coffee shop. At the beginning of chapter 2 we are in the coffee shop. Minor confusion as the viewpoint has changed, but the confusion goes away quickly.
7. I like that you are characterizing though actions & reactions, rather than simply telling us what characters are like. You are showing and not telling.
B. Suggestions.
1. Tread carefully in depictions of the Holy Spirit. We are told in Matthew 12:31-32 by Jesus himself that the one unforgivable sin is blasphemy against the Holy Spirit. Not saying that what you have written is blasphemous. Simply saying that making God a character in a story is not something to be done lightly. You might want to consider making Gabriel an angel or a lesser spirit, and changing his name to something other than Gabriel to avoid confusion with the Gabriel of the Bible.
2. To some extent this seems to be a mystery story. There are two basic approaches to writing a mystery. One is the Mary Roberts Rinehart approach of plotting a crime story first, then writing the mystery as a sequel to that back story that will be revealed at the end. The other is the Ed McBain approach of starting with a mystery--some impossibility or puzzle or unexplained matter--then coming up with all kinds of possible explanations, and not knowing the end until you get to the end, finding out the ending as you come to it. Chester Gould wrote Dick Tracy that way, striving each week to get Dick Tracy into some impossible situation, then wracking his brains throughout the next week trying to figure how to get Tracy out of the jam.
But you can bounce back and forth between these two approaches. Even if you have written the last chapter first as Rhinehart would do, you can shift over to the other approach at anytime and go for a different ending if a better ending occurs to you as you write the mystery. And even if you start off like McBain with a puzzle and no answers, you can stop and figure out the ending at any time.
Seth seems to be wearing a neon sign saying he's the killer. If he's just a red herring, that's okay, although you're laying it on a bit thick. If he actually is the killer, I think the reader will be disappointed by the obviousness of it when he or she gets to the end.
3. To some extent this looks like it may be a story of character--perhaps even a story of two characters. Perhaps the best approach to writing a story of character is to impact the character--hit the character with something that shakes the character to his or her core, a crisis that will leave the character a different person no matter how he or she might handle it. Perhaps you are already headed in that direction. If not, it is something to consider. But if Gabriel is the Holy Spirit, it would be hard to go in that direction without being irreverent. Luke would be easier to impact. What would turn Luke's world upside down? What would be his "life's greatest challenge," his greatest test of character that would rock his world view or his sense of self?
4. Minor point #1--Too much is going on in the sentence where the mother hands the baby over to Jesse/Gabriel. It is pretty much a physical impossibility to exchange money and baby, and stalk down the street simultaneously. That sentence needs to be broken down into two or three sentences.
5. Minor point #2--In giving a description, you want to start with the fundamental image. You didn't tell us until eight paragraphs after his introduction that Seth has "overgrown silky blonde hair falling into his eyes." I had pictured Seth with dark hair to match his dark creepiness. Since I had already pictured Seth differently in my mind's eye, I had to revise my mental image of him, which disrupted the reading of the story, taking me out of the story world. I would have preferred that Seth had entered the story with the sentence: "The tall, blonde, lanky lab tech looked up from his computer screen." Then, when we read eight paragraphs later that his hair is overgrown and falling into his eyes, it is merely additional detail, and not a significantly different image.
But enough with the nit-picking. Wishing you well with writing the remainder of the story.
