The parable emphasizes the seriousness of the present. What really matters is what we do right now. The story calls us to a real sense of responsibility for the poor and the oppressed. And all this in reference to God's judgment and criterion.

One is not guilty only when one commits evil, but also when one does not act. The rich man's sin consists in the fact that he has not shown any concern, that he has been blind to the plight of the poor.

Herman Hendrickx
The PARABLES of JESUS
Studies in the Synoptic Gospels