Robert Jordan is an American volunteer fighting in Spain for the Loyalist Cause during the Spanish Civil War in the 1930s. An expert in using dynamite, Jordan, the protagonist, climbs a mountain with an elderly Spanish peasant named Anselmo who speaks a form of archaic Castilian Spanish. The men are tired and hungry but they keep on trudging upwards step by step. Jordan's mission is to blow up a bridge, work which he has successfully undertaken in the past, and it remains Anselmo's job to guide Jordan through the desolate mountains to a position where he can carry out his task. Jordan feels good about his guide and is amazed by the physical endurance of one so old, and he trusts him. But, he is worried about other things.
An idealist, Jordan thinks back to the orders he received from the Russian General Golz. He must carry out his mission to dynamite the bridge in a very different manner from earlier missions and this causes him concern. Golz explains to Jordan that in the past, missions such as these have ended badly and this increases Jordan's stress level. They continue on their upward trek until they meet Pablo, the gloomy leader of a guerilla band whom Jordan recruits in his effort to blow up the bridge. Pablo, once a brave, strong fearless man, is exhausted from fighting and does not trust Jordan, the foreigner. Anselmo denigrates Pablo by pointing out that now he has acquired property he has grown soft and has forgotten about the Cause. Jordan considers Pablo to be dangerous, to be "going bad fast," so to speak, and looks apprehensively to the future (16). If Pablo ever acts as if he is his friend, he realizes, he could be doomed.
At this point, Jordan castigates himself for his unusual negative attitude. He is a positive individual like Golz and Anselmo. Soldiers need to be happy, he believes, because happiness lends them a form of immortality which increases their chances for survival. And, now he too has become increasingly gloomy, and turned into a mere bridge-blower: "and if you keep thinking like that, my boy, you won't be left either" (17).
From the beginning, an ominous tone of foreboding permeates Ernest Hemingway's For Whom the Bells Toll. When he forgets Anselmo's name, Jordan is alarmed and considers it a bad sign. Gloominess pervades Jordan's mind and he sinks downward into negative introspection. It is as if the sun cannot shine. Trust is also an issue from the beginning. Jordan wonders whether he can trust Anselmo, whom he likes, and does not trust Pablo at all. Golz, the Russian general, mistrusts the Spanish while Pablo, the Spanish guerilla leader, who has just acquired five beautiful horses after killing two Monarchist guards, mistrusts the foreigner Jordan. "What right have you," Pablo says to Jordan, "a foreigner, to come to me and tell me what I must do?" (15).
Pablo, who has earlier lived in abject poverty and who fought with nothing to lose, has now acquired valuable property and has become less interested in fighting for the Loyalists. Jordan plays the role of the solitary hero then, a figure seen throughout many of Hemingway's works, without a band a comrades to back him up. He will trust or distrust others in the novel as he encounters them.
Regarding characterization, Hemingway uses very little narrative description and reveals much regarding his characters through dialogue and physical attributes, believing particularly that the face reveals a great deal. For example, he doesn't tell us in narrative detail that Golz and Pablo are opposing characters, he shows us in their physical characteristics. Golz has "hawk eyes," someone we could say that sees everything, while Pablo's eyes are small, in opposition to Golz's, and set "too wide apart."