...I don't believe the word "eternal" has a place in scripture.
Wow.
There is a difference between the word "immortal" and "eternal."
Okay, sure, but what is immortal is eternal, with regard not necessarily to eternity past but eternity future.
At the present time we are mortal which means we can never be eternal; we will die.
This is a conflation. You're right that for now we are mortal beings, and will die (unless Jesus returns first). But when He returns, we will then be made immortal... and will live with Christ into eternity, which by definition will have no end, and thus we will be eternal. Even beyond this, there is a sense in which we have eternal life now... not that it has actually come to be, yet, but in that it is certain.
We will be given immortality and from then on we can never die.
Right.
...they went right back to their graves.
Well, at some point, yes. It might not have been "right back," as in immediately; think Lazarus... <
smile> But eventually, yes. We can't know how long they remained alive. And... they will be resurrected with us at the end of the age, along with eeeeeeeeeeeeeeeeeverybody else, and face the final Judgment... with us, God's elect, on Jesus's right (Matthew 25). <
smile>
They will be resurrected through God's wrath via the lake of fire.
Well, they will be on Jesus's left in the final Judgment (Matthew 25:41), and will go away... depart... as a result of the final Judgment (Matthew 7, 25), into God's eternal judgment, which is the second death of Revelation 20. <
shudder> Our God is a consuming fire (Deuteronomy, Hebrews).
Yes, judgment is now for God's Elect, who God chastises now so that they will not have to endure God's wrath later.
This is His fatherly discipline, which He does for those He loves, and yes, can take the form of lesser judgments. But the final Judgment is yet to come, and we will stand for it, along with everybody else. The difference is that, having been redeemed, we will have an Advocate, in Whose righteousness we will stand.
Only God the Father is able to think in the past, present and future ALL AT the same time.
Well, yes... God is the Ruler of time, which is part of His creation, which He is outside of and above. So everything which is for us past, present, or future at any one point in time, is present for Him. He is in what we sometimes call the eternal now. His very Name indicates this to us. He is the great I Am. And self-existing, from eternity past to eternity future.
Though you may not fully comprehend what I am saying now...
It really, to us finite creatures, is incomprehensible. I mean we can understand the things in concept, but we really cannot completely comprehend them, cannot completely grasp them.
My point in all of this, concerning the resurrection of "many" (but not all) of the OC saints, at the time of Jesus' mortal death is this: NO OC saint ever had the permanent indwelling of God's Holy Spirit.
This is refuted by Ezekiel 11:19-20 and Ezekiel 36:26-27, among other Old Testament passages ~ "O house of Israel... I will take you from the nations and gather you from all the countries and bring you into your own land. I will sprinkle clean water on you, and you shall be clean from all your uncleannesses, and from all your idols I will cleanse you. And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. And I will put my Spirit within you, and cause you to walk in My statutes and be careful to obey My rules." And in reading Hebrews 11, it is clear that we are all saved the same way, through faith, by the Spirit.
Because Jesus had not shed His blood for sins yet...
But all the sacrifices that the Israelites were told to make... particularly the lamb without blemish of Leviticus... pointed to Jesus. The only difference between us now and the Israelites of old is that they were looking forward to the coming of the Savior, and we are looking back on it. In faith. As the writer of Hebrews says at the outset of His letter, "Long ago, at many times and in many ways, God spoke to our fathers by the prophets, but in these last days he has spoken to us by his Son" (Hebrews 1:1-2). And Jesus Himself says the entire Old Testament ~ Moses and the prophets ~ was about Him (John 5:46, Luke 24:27. 44).
Grace and peace to you both.