In today's readings on this feast that celebrates two of Paul's closest associates, we are reminded that a key to unlocking Paul's theology is understanding that God's grace is a gift to all and that it comes to us freely.
Here we encounter that remark from Mark about the unforgivable sin against the Holy Spirit ... only after Jesus says: "...all sins and all blasphemies that people utter will be forgiven them."
This means for us that really our main concern is to examine our consciences regularly and then take ourselves to the loving forgiveness of the Sacrament of Reconciliation ... to share fully in the loving care of Jesus, our Redeemer.