In her commentary on Works of Love, Amy Laura Hall describes Kierkegaard’s goal as elaborating the ways that we fail to love. Here is a good one:
In this story, a father commands two sons to go to work in his vineyard. The first son refuses to go but then changes his mind. The second son agrees to go but then does not. …
Kierkegaard’s readers are to identify with the brother who, in saying yes to his father’s request, inadvertently trapped himself within a context of judgment. In his lengthy exposition of this parable, Kierkegaard explains that the son who eagerly promises but does not recognize the import of his promise is “facing the direction of the good” but “is moving backward further away from it” (WL, 94). The better way is actually that of the first son, who interprets soberly the stark demands of an affirmative answer and thus says no: “The yes of the promise is sleep-inducing, but the no, spoken and therefore audible to oneself, is awakening, and repentance is usually not far away” (WL, 93).
"The yes of the promise is sleep-inducing, but the no… is awakening, and repentance is usually not far away."