It may be said:

This is part of the perfection of their virtue, fear, servitude to Allah, and humility. Among the benefits of that from which one repents (1) is that it perfects the servant’s servitude, increasing him in fear and submission, and thereby Allah raises his rank. Their refusal to intercede is likewise among the means by which Allah raises their ranks. Allah Most High’s wisdom in this is that the intercession should ultimately fall to the one whose former and later sins Allah has forgiven.