Juan Rulfo opens in the story in media res— in the middle of the narrative—as Juvencio begs his son, Justino, to help him with the debacle that he's in. The reader doesn't know right away what's happening; they only know that law enforcement is planning to kill Juvencio and that his son thinks that helping will only exacerbate the problem and, potentially, threaten his life, too. While Juvencio waits, tied to a post, he thinks about how the misfortune came to pass:

Who would've thought that old business that happened so long ago and that was buried the way he thought it was would turn up? That business when he had to kill Don Lupe. Not for nothing either, as the Alimas tried to make out, but because he had his reasons. 

Here, Rulfo shows that, even with the passage of time, Juvencio still believes he had to kill Don Lupe. He doesn't have remorse for his crime, really. Instead, he sees only that he was forced to do it because of the desperation he felt from his situation. It's not clear that Juvencio deserves the mercy he craves, because he is still the same selfish man that killed his friend.

This mentality is further displayed when he thinks about how he got away with the crime. He doesn't think about the struggle of Don Lupe's widow, who died soon after her husband, or the children that had to be raised by family. He only thinks of them as impediments to be removed. Rulfo writes:

I figured then that with about a hundred pesos everything could be fixed up. The dead Don Lupe left just his wife and two little kids still crawling. And his widow died soon afterward too—they say from grief. They took the kids far off to some relatives. So there was nothing to fear from them.

His lack of compassion for other people is also evident in the way he begs his son to go talk law enforcement out of punishing him. He isn't concerned that law enforcement will turn on his son. He isn't worried about what happens to the rest of his family: Juvencio is only worried about himself.

However, his preoccupation with the past is mirrored by that of the colonel who is going to execute him—the man is the grown son of Don Lupe. When he explains what he knows about his father's death to Juvencio, he says:

Later on I learned that he was killed by being hacked first with a machete and then an ox goad stuck in his belly. They told me he lasted more than two days and that when they found him, lying in an arroyo, he was still in agony and begging that his family be taken care of.

As time goes by you seem to forget this. You try to forget it. What you can't forget is finding out that the one who did it is still alive, feeding his rotten soul with the illusion of eternal life. I couldn't forgive that man, even though I don't know him; but the fact that I know where he is makes me want to finish him off. I can't forgive his still living. He should never have been born.

It's clear that he won't stop the execution. He does display the mercy that his father never received when he lets Juvencio get drunk first so that he doesn't feel the pain from the firing squad. Juvencio dies, and, when his son collects him, he thinks that his family won't recognize the body.