The young man, whose name was Robert Jordan, was extremely hungry and he was worried. He was often hungry but he was not usually worried because he did not give any importance to what happened to himself and he knew from experience how simple it was to move behind the enemy lines in this country. It was as simple to move behind them as it was to cross through them, if you had a good guide. It was only giving importance to what happened to you if you were caught that made it difficult; that and deciding who to trust. (1.53)
Robert Jordan is an excellent soldier because he doesn't fear death. In part that's because he's pretty experienced and pretty sure of himself, but deep down it's because he doesn't really care what happens to himself. He doesn't have a reason for living besides the cause. It's as if he'd give his life because he's got nothing better to do.
They are awfully good horses, though, he thought, beautiful horses. I wonder what could make me feel the way those horses make Pablo feel. The old man was right. The horses made him rich and as soon as he was rich he wanted to enjoy life. Pretty soon he'll feel bad because he can't join the Jockey Club, I guess, he thought. (1.217)
In contrast to Robert Jordan, Pablo is desperately attached to his own life, and the horses he's acquired are his prized possession (remember, Pablo used to be a horse trainer). Because of that attachment, he's unwilling to risk his life. This is what lies at the roots of Pablo's "cowardice."
"I am afraid to die, Pilar," he said. Tengo miedo de morir. Dost thou understand?"
[…] "All my life I have had this sadness at intervals," the woman said. "But it is not like the sadness of Pablo. It does not affect my resolution." (9.63; 67)
Pablo's only direct admission of a fear of death – this is a moment when it's uniquely easy to sympathize with his character. That fear of death is called "sadness," but it's not necessarily easy to see how sadness is connected to fear. There seems to be more to Pablo's "sadness" than just not wanting the party to stop (i.e., it's not just that he wants to keep enjoying life). There's a hopelessness about it, which is why it leads to inaction. Pilar understands it, though unlike Pablo she is capable of resisting it. What has really caused it?
If he had known how many men in history have had to use a hill to die on it would not have cheered him any for, in the moment he was passing through, men are not impressed by what has happened to other men in similar circumstances any more than a widow of one day is helped by the knowledge that other loved husbands have died. Whether one has fear of it or not, one's death is difficult to accept. Sordo had accepted it, but there was no sweetness in its acceptance, even at fifty-two, with three wounds and surrounded on a hill. (27.62)
El Sordo's about to die, and here we see the thought expressed that dying is something one does alone. It doesn't matter to you that other people have died, or that they died in such and such a way, or for such and such a reason. All that matters is that you're dying. Any way you look at it, you're still faced with the same thing: ceasing to be. And whether or not you accept that (admit it to yourself honestly), it's not pleasant. El Sordo's attitude here is an example of Hemingway's (macho?) ideal of "taking it straight."
Dying was nothing and he had no picture of it nor fear of it in his mind. But living was a field of grain blowing in the wind on the side of a hill. Living was a hawk in the sky […] Living was a horse between your legs and a carbine under one leg and a hill and a valley and a stream with tress along it and the far side of the valley and the hills beyond. (27.64)
El Sordo's thinking that death isn't something mysterious: it's just nothingness. Period. Everything stops. That's part of what makes it so hard to imagine, and hard to accept. Any image or sense one might have of what it would be like, fearful or beautiful, would come from the living world that we've spent all of our existence in. There's a wistfulness here for nature and the vibrancy of natural life, which makes sense, given that El Sordo loves hunting and being "in the wild."
He looked very small dead, Robert Jordan thought. He looked small and gray-headed and Robert Jordan thought, I wonder how he ever carried such big loads if that is the size he really was. (43.128)
It's only when Robert Jordan sees Anselmo's dead body that he sees him as he physically really is: small and old-looking. When he was alive, his animation and personality (his "spirit"?) had changed the way he looked. But with death that animation has vanished, and Anselmo has in an instant become another inert thing. There's something very anticlimactic about death that way, which Hemingway's matter of fact prose conveys quite effectively.
Lying there, by Agustín, watching the planes going over, listening for firing behind him, watching the road below where he knew he would see something but not what it would be, he still felt nub with the surprise that he had not been killed at the bridge. He had accepted being killed so completely that all of this now seemed unreal. Shake out of that, he said to himself. Get rid of that. There is much, much, much to be done today. But it would not leave him and he felt, consciously, all of this becoming like a dream. (43.192)
In the face of expected death, Robert Jordan had begun to let go of life already as a reaction. Perhaps it is a way of making leaving it all psychologically easier? Since Robert Jordan didn't die, the world around him now feels unreal. It's interesting to note that Robert Jordan experiences the same sense of unreality, or of being lost in a dream, as a reaction to his love with Maria.
He looked down the hill slope again and he thought, I hate to leave it, is all. I hate to leave it very much and I hope I have done some good in it. I have tried to with what talent I had. (43.373)
The only thing that really bothers Robert Jordan about dying is leaving everything he cares about behind. And Robert Jordan now cares about a lot. Kind of a big change from the beginning of the book. That caring makes dying more painful. But it also gives a new resolve to his sacrifice. He is giving himself up for something (fill in the blank: his friends, the Republic, humanity, the world?) he appreciates much more than he did before.
Who do you suppose has it easier? The ones with religion or just taking it straight? It comforts them very much but we know there is no thing to fear. It's only the missing that's bad. Dying is only bad when it takes a long time and hurts so much that it humiliates you. That is where you have all the luck, see? You don't have any of that. (43.383)
Death doesn't pose that much of a problem for Robert Jordan, who "takes it straight" (very Hemingway male). The comforts of belief in an afterlife don't really matter to him, and add an unnecessary kind of uncertainty. Death is only particularly troublesome if it's painful and humiliating (he hasn't started feeling pain yet). Does one get the sense that he's trying to convince himself he believes this?
It's wonderful they've got away. I don't mind this at all now they are away. It is sort of the way I said. It really is very much that way. Look how different it would be if they were all scattered out across that hill where that gray horse is. (43.384)
Robert Jordan own death is made much easier to accept because his friends escaped. This in part because, by dying, he's helping them escape, so he can give his death a purpose. But there's something deeper: he feels that, so long as they live, a part of him will survive as well. That's "what he said" (to Maria), in case you're wondering.