In this chapter, Saul is terrified of the Philistines and consults with a medium.
This chapter begins with yet another awkward exchange between David and Achish. In this case, Achish is asking David to go with him to fight against Israel, and David (in keeping with his deception) agrees to go and fight against Israel. Spoiler: David never has to actually fight against Israel. But I have to wonder what David would have done if he found himself in a battle against Israel. Would he have turned against Achish, or fled, or actually fought his own people? None of these are good options, considering he is staying as a guest of Achish, but ultimately his loyalty is to the LORD and his own nation.
Regardless of what he would have done, David has no choice but to continue to deception until he finds a way out. In the next chapter, David gets lucky and finds a way out of the battle. But this situation could have ended very badly for him.
Starting in verse 3 we see that things are going much worse for Saul than they are for David, however. Saul finds himself once more arrayed for battle against the Philistines, and like in earlier conflicts against the Philistines, his heart trembles with fear, but the LORD did not answer him.
In 1 Samuel 14:37, the LORD did not answer Saul, because of Jonathan who unknowingly violated Saul's oath. Interestingly, that was after Jonathan won a great victory over these same Philistines. Now Saul is fighting the Philistines again, but it is his own sin that prevents the LORD from speaking to him. Saul sinned by not destroying the Amalekites and taking the plunder, sinned again by offering a sacrifice instead of waiting for Samuel, sinned by trying to kill David several times, sinned by killing Ahimelech and the families of the priests, and now that the LORD is not answering him, Saul sins again by seeking out a medium.
Out of his many problems, we can see that Saul turns first to Samuel, even going through a medium, rather than turning to the LORD. I think this captures a lot of Saul's dysfunction in a nutshell.
Another way to capture the absurdity of this situation is that Saul murdered a bunch of priests and now he's trying to hear from the LORD? And because he can't, he tries to call back the one priest that he had a somewhat decent relationship with? But in doing so, he violates the covenant which says that any mediums and spiritualists should die, precisely because contacting the spirits of the dead is a way for people to seek direction or guidance without going to the LORD.
Saul has been acting under the direction of evil spirits, doing evil deeds, and separated from the LORD for years now. That Saul thinks the LORD will continue to support his reign is absurd, and Samuel pretty much tells Saul how it is.
This chapter is quite unique however, as it is the only time in the entire bible that anyone visits a medium or spiritualist, and I think it's worth spending a few minutes analyzing the details thereof.
First of all, note that this chapter gives us very little (almost nothing) about the actual rituals or incantations involved in bringing a spirit of the dead back to this world. So we aren't really told how the woman did this, only that she was capable of it and had a reputation such that Saul knew how to find her.
Secondly, it's very interesting that she recognizes Saul only when "the woman saw Samuel". What is it about seeing Samuel that revealed Saul's deception to her? Did Samuel tell her?
Third, how is it that this woman had the power to call back Samuel's spirit? The bible does not directly answer this point, so most of what you will hear people say about it is learning by inference. What I've heard most commonly from Christian sources is that spiritualism does not commune with the spirits of the dead, but rather with demons masquerading as the dead. As such, the woman realized that something was wrong when Samuel appeared rather than the "normal spirits" that would talk to her. By inference, this is possibly how she would know that Saul was there.
Of course, this doesn't actually answer the question of how she called back the real Samuel to converse with Saul. The aforementioned sources usually assert that God made a special dispensation to bring Samuel to speak to Saul. That is, it was not the woman's rituals or power that brought Samuel, but rather the LORD who brought Samuel to speak to Saul, and did so through the woman. It's a similar argument to what happens when God speaks through Balaam in Numbers 22-24. By all regards, Balaam is a pagan prophet who operated primarily through divination (animal sacrifice and reading or manipulating the entrails). However, God utilized Balaam to pronounce three blessings over Israel, contrary to Balak's intention.
In this case, the conventional argument is that God is similarly using this unnamed woman to bring Samuel to speak to Saul, and that it was not the woman's spiritualism that accomplished the task. Even so, I find this chapter quite interesting because it's one of a handful of incidents where the LORD uses idolatrous practices to further his own purposes.
Fourth, note that Saul cannot see Samuel; as is commonly true for seances like this. Saul relies on the medium to communicate Samuel's words and appearance to him.
Lastly, this is the first time in the book that anyone told Saul directly that David would take his kingdom. He's suspected it for years, but only now does he learn it for sure.
Sorry as it is to say, these are the last recorded words of Saul. A couple chapters later Saul is going to die in battle against the Philistines, and go "be with" Samuel, wherever it is that Samuel happens to be. I wish I could say that Saul ended well, but we can all see that Saul's end is pretty dishonorable. Like many others in the bible, Saul's life is an example and warning to us, and in the last ~20 chapters I have written about Saul extensively, so I'm not going to repeat that now. Saul's story is a grim warning, but if there's one thing that makes me hopeful, it's when Samuel says that Saul will "be with him" that next day. In the first place, this means that Saul is going to die. But in the second place, if we imagine Samuel being in heaven, then we can reason Saul might also go to heaven because that is where Samuel is.
Of course, to this point I have said almost nothing about heaven or hell because the bible has said almost nothing about heaven or hell. Addressing this subject would take considerable effort, and I can't do a good job at it without referring to many New Testament (NT) passages. But who can imagine a subject more deeply embedded in popular culture and (frankly) misunderstanding than heaven or hell.
I'll start with the basics here, if I can, and try to discuss this subject more thoroughly later. There is a difference between the way that heaven is represented in the OT and the NT. The NT representations of heaven are both diverse and complex, so I will leave that subject untouched. The OT tends to be a lot simpler and more allusive. The OT most commonly refers to "Sheol", which is variously translated as "the grave" or "hell", but it is not hell as modern readers would understand it. In verse 15, Samuel criticizes Saul for "disturbing" him. By implication, Sheol for Samuel is a place of rest, and for the righteous, that is how it is most commonly understood.
Typical OT descriptions of Sheol are a place of silence, rest or peace. It is neither the heaven nor hell of modern conceptions, but a lot closer to purgatory, a sort of resting place. Christians would likely view it as an intermediate resting place, preceding judgment by God. But even this is scarcely made clear by OT sources.
So anyway, what makes me hopeful is that perhaps somehow Saul will find himself in a place of rest with Samuel, and while his life ends poorly, perhaps he will find rest in death that he did not find in life.