I agree that God says he will not break the Covenant in Psalm 89. but I believe the issue is, is the Covenant in Psalm 89 the same as the Covenant in Jeremiah 31, Hebrews 8?
Do you believe there is only one Covenant? I believe there is a covenant mentioned in Genesis 9 about God not destroying the Earth by flood. would that be the same Covenant as one of the ones mentioned above?
I believe that the Covenant that God makes with Abraham that's talked about in Galatians chapter 3 is ratified by God, and I think that happens before the giving of the law through Moses. so that Covenant would have been ratified long before Jesus shed his blood.
In Galatians chapter 4 it speaks of 2 Covenants. the first Covenant is the one from Mount Sinai, which apparently is the one you don't really want to be part of, compared to the second Covenant which relates to the Heavenly Jerusalem.
Yes I beleive it is the same because if we look at PS 105 there is no doubt that the Covenant made with Abraham was continued with Israel:
Psalms 105:6-10, “O seed of Aḇraham His servant, Children of Ya‛aqoḇ, His chosen ones! He is יהוה our Strength; His right-rulings are in all the earth.
He has remembered His covenant forever, The Word He commanded, for a thousand generations,
The covenant He made with Abraham, And
His oath to Yitsḥaq, And
established it to Ya‛aqoḇ for a law,
To Yisra’yl – an everlasting covenant.”
Jeremiah 31:33, “For
this is the covenant that I will make with the house of Yisra’yl: After those days, says YHWH: I will put My Law (Torah/Instructions) in their inward parts, and write it in their hearts, and I will be their Strength, and they will be My people.”
and about Galatians Paul also says it is the same covenant as Abraham as with Messiah:
Romans 9:6-8, “However, it is not as though YHWH's plan had failed. For it is not everyone who is a descendant of Yisra’yl who belongs to Yisra’yl. Nor, just because they are his descendants, are they all Abraham's children; but: In Isaac will your seed be called. That is, it is not those who are the children of the flesh who are YHWH's children; but it is the children of the promise who are regarded as Abraham's seed.”
Galatians 3:27-29, “For as many of you as were immersed into Messiah have put on Messiah. There is not Yehuḏi nor Greek, there is not slave nor free, there is not male and female, for you are all one in Messiah יהושע. And if you are of Messiah, then you are seed of Aḇraham, and heirs according to promise.”
and PS 105 and Jer 31 show the COvenant with Abraham is the same as with Israel... I think and this is me summing it up, YHWH basically made a Covenant for all mankind that would partake in it, and at different times different people did, malak-zadiq was the high priest at one point than men were, yet same covenant, men died and new priests came, same covenant, it seems like i said before that the difference between a physical priesthood and living under that would have been such a ridical chage to have Yahshua as High Priest, and some of the allegory is spot on, because the levitical priesthood's "atonement" was much harder "work" on the average person than what the aversage person has under the HighPriest Yahshua... A lot there but that is basic view. but again those first 2 passages I posted are clear IMO.