Saint Catherine heard God say to her: This is the sin that is never forgiven, now or ever: the refusal, the scorning of my mercy. For this offends me more than all the other sins they have committed. So the despair of Judas displeased me more and was a greater insult to my Son than his betrayal had been. Therefore, such as these are reproved for this false judgment of considering their sin to be greater than my mercy (…) They are reproved also for their injustice in grieving more for their own plight than for having offended me.
They are being unjust in this because they are not giving me what is mine, nor taking for themselves what belongs to them. It is their duty to offer love and bitter heartfelt contrition in my presence for the sins they have committed against me. But they have done the opposite. They have lavished such tender love on themselves and felt so sorry about the punishment they expect for their sins! So you see how unjust they are. They will be punished, therefore, on both accounts. They have scorned my mercy, so I turn them over to my justice.The Dialogue of Saint Catherine of Siena, Ch 37, via DailyGospel.org