I always wondered why the phrase "firm purpose of amendment" sounded so technical, even before I knew there were other meanings for amendment - e.g. in the garden, in the constitution. But the phrase answers the warning given in the Book of Sirach this morning about presuming God's forgiveness before or during committing sin.
Critics who mock the Sacrament of Reconciliation as somehow giving permission for Catholics to continue sinning with impunity miss the mark. We do not apologize to each other for wrongs in order to continue offending them and it is the same with God.
A firm purpose of amendment must be made in loving seriousness.