If God didn’t do this in reaction to what we humans did, then what prompted it?
God's Holy plan from the beginning. God doesn't just know the beginning from the end, He determines the beginning from the end. Otherwise, He is subject to time and the random decisions of men. He is simply one more cog in the universe, etc. God is much more powerful than that.
Since not even St. Paul was assured, how is it that you guys are?
Paul certainly was assured. For example:
2 Tim 4:6-8 : 6 For I am already being poured out like a drink offering, and the time has come for my departure. 7 I have fought the good fight, I have finished the race , I have kept the faith. 8 Now there is in store for me the crown of righteousness, which the Lord, the righteous Judge, will award to me on that day — and not only to me, but also to all who have longed for his appearing.
Paul understood that it is by grace we are saved, through faith. He knew he had received grace and he knew that he had true faith. So, he knew that he was saved.
Wow. And none of this relates to anything of your doing or not doing. Nothing of what you do or not do relates to anything. You are saved and no sin matters. This is fantastic.
It sounds to me that we use the word "matters" fundamentally differently. :) By your responses it appears that to you the only things that matter are those works that make us more acceptable to God for Him to let us into Heaven. Obviously the Reformed do not share this view. We believe that Christ did the thing that matters.
Amen, FK. Preach it!