I'm well aware of the debates (plural) that surround both the Abrahamic and New Covenants, even within Reformed Theology. So, what? Maybe that's a reason I don't subscribe to Covenant Theology! Since you take the conditional side (probably to both), then identify the conditions in the NC with chapter and verse, please. But of course, you won't be able to do so; for we both know there are no conditions stipulated in Jer 31, 32 or Ezek 36. The NC is strictly unilateral -- filled with I WILL, I WILL, I WILL (God speaking) -- with no YOU WILL anywhere to be found. And this is be expected since the NC is so very much UNLIKE the Old (Jer 31:32), which indeed was a conditional, bilateral covenant.
not being able to reconcile the demands of the NT Gospel with the unconditional promises of the New Covenant that preceded the first advent by several centuries?
Even though this is all still about TULIP (the 1Tim discussion being about the L in TULIP standing for Limited Atonement) I've separated the 1Tim4:10 discussion from this above quoted one.
I'm also familiar with this debate within the Reformed camps over conditional vs. unconditional covenants. I don't expect to resolve anything with you, but it's an interesting discussion that also remains unresolved within the Reformed systems.
It seems at heart a pretty simple problem. Under the U in TULIP, standing for Unconditional Election, if there are any conditions in the Covenant, then TULIP loses the U.
It's been some time, but I too have been taught the covenants and how they've been classified as unilateral vs. bilateral, unconditional vs. conditional. Honestly, to begin with, this too is something I've for the most part set aside in my personal studies. In my experience men simply make too many mistakes with the Text. I can go back and draw upon these interpretations if I need to.
You mention the Abrahamic Covenant. It's classified as unconditional. Then we read a verse like this one and it at least makes me wonder if we know what we think we know:
NKJ Gen 26:2-5 Then the LORD appeared to him and said: "Do not go down to Egypt; live in the land of which I shall tell you. 3 "Dwell in this land, and I will be with you and bless you; for to you and your descendants I give all these lands, and I will perform the oath which I swore to Abraham your father. 4 "And I will make your descendants multiply as the stars of heaven; I will give to your descendants all these lands; and in your seed all the nations of the earth shall be blessed; 5 "because Abraham obeyed My voice and kept My charge, My commandments, My statutes, and My laws."
So, simply put, I now just read and analyze Scripture as best I can in Christ in Spirit. Among all the "I will" statements you made emphatic for your purposes, some of which we can also see in these verses, exists a causal clause. The faith, obedience, and faithfulness of Abraham is well covered in Scripture. It's things like this in Scripture that made me begin to question all the authoritative pulpit pounding of men and their systems.
In order for you to protect TULIP, we're now going to be presented with a distinction and separation between the Gospel of Jesus Christ which contains conditions for men, and the New Covenant "I WILL" statements of God positing that there are no conditions in the NC.
So, you said you can present this case. Please do. Start where you will. Maybe the big picture of why and how the Gospel and the NC are separate in this view. My one request is that you take it slowly so both of us can try to keep these posts more brief.