Given that those who believe the gospel and are saved, are elect through the foreknowledge of God (1 Peter 1:2), God knew right from the start who was going to be saved.
Now, I am not supporting predestination here. There is a difference between foreknowledge through the omniscience of God, and God pre-determining who is going to be saved and who is to be reprobate.
Therefore, given that those through God knowing all those who are going to be saved from Adam until Jesus comes again, the names of the elect are already written in the Book of Life. Therefore when Jesus suffered on the cross, He suffered and shed His blood for all those already written in the Book of Life.
I like your ideas.
My beliefs on this matter are speculative. And that is not mine or anybody else's fault. In the Old Testament God was interested in the "Holy Seed"....the Hebrews...Israelites...Jews....pretty much at war against everyone else.
Then we come to God so loved the world...no exceptions given.
1st John 2:2 "and He Himself is the propitiation for our sins; and not for ours only, but also for those of the whole world."
Then when most of Jews rejected Christianity it was offered to the rest of the world...Pagan...Gentiles.
But I believe the process of change, in regard to the relationship between God and the world, and sin, and salvation, started with the birth of Christ. I believe it is a progression that is still not complete.
Luke 2:9-12
And there were in the same country shepherds abiding in the field, keeping watch over their flock by night. And, lo, the angel of the Lord came upon them, and the glory of the Lord shone round about them: and they were sore afraid. And the angel said unto them, Fear not: for, behold, I bring you good tidings of great joy, which shall be to all people. For unto you is born this day in the city of David a Saviour, which is Christ the Lord. And this shall be a sign unto you; Ye shall find the babe wrapped in swaddling clothes, lying in a manger.
So am I right, was the relationship between God and the whole world changing in the NT? What was going on with sin and salvation, what was happening to sin and salvation upon the advent of Christ's birth, during His ministry...before Christ was crucified and then after and then after He ascended to His Father and then when He appears again...1st John 3:2 "Beloved, now we are children of God, and it has not appeared as yet what we will be. We know that when He appears, we will be like Him, because we will see Him just as He is." What does that all mean?
I believe there were significant changes that were in progress throughout the NT. If I try to explain them, people are just going to say that, that is not biblical...how true! The Bible just does not get into detailed explanations on this. But I have my own beliefs.