What is the covenant formula that runs through the whole Bible?
The phrase 'I will be their God and they will be my people' appears more than a dozen times from Genesis 17 to Revelation 21, always in the same grammatical structure, tracing one continuous covenant relationship across every major covenant.
There is a sentence that runs through the entire Bible — from God's conversation with Abraham in Genesis 17 all the way to the final vision in Revelation 21. It appears in the Abrahamic covenant, the Mosaic covenant, the Davidic covenant, the New Covenant, and the consummation. It is always essentially the same sentence: I will be your God and you will be my people.
Here are the key instances. In Genesis 17:7, when God establishes his covenant with Abraham: "to be to you God and to your seed." In Exodus 6:7, when God commissions Moses, he explicitly recites the Abrahamic formula: "I will be to you God." In 2 Samuel 7:14, the Davidic covenant adopts the royal variant: "I will be to him Father, he will be to me Son." Then in Jeremiah 31:33, the New Covenant:
"I will be their God, and they will be my people." — Jeremiah 31:33
Ezekiel 37:27 uses the same Hebrew words, verbatim, in the parallel vision of restoration. And at the very end of Revelation, when all things are new:
"They will be his peoples, and God himself will be with them as their God." — Revelation 21:3
Four Hebrew terms carry this formula in every instance: hayah (H1961, "to be"), elohim (H0430, "God"), am (H5971, "people"), and berit (H1285, "covenant"). The grammatical structure is identical each time: a form of "to be" governing a prepositional phrase identifying God and people in mutual belonging. Vocabulary analysis shows 43.8% shared terms between Genesis 17:7–8 and Jeremiah 31:31–34.
The formula is never restarted for a different people. It is repeated and intensified across four covenant administrations — Abrahamic, Mosaic, Davidic, New — for the same covenant community. By the time it reaches Revelation 21:3, the plural laoi ("peoples") broadens the formula to every nation, which is exactly what Genesis 12:3 promised when God told Abraham "all the families of the earth will be blessed through you."
Notice also that the "everlasting" designation — berit olam (בְּרִית עוֹלָם, H1285 + H5769) — applies to the Noahic covenant (Genesis 9:16), the Abrahamic (Genesis 17:7), the Davidic (2 Samuel 23:5), and the New Covenant (Jeremiah 32:40; Ezekiel 37:26). One permanence category spans all of them. The formula and its permanence language are telling the same story: one relationship, one trajectory, four administrations.
For the full canonical trace and the olive tree argument in Romans 11, see "One Plan, One People" — The Covenants from Abraham to Christ, section "The Covenant Formula: One Thread from Genesis to Revelation."
Does the book of Hebrews say the Mosaic covenant is obsolete?
Yes, explicitly. Hebrews 8:13 uses the perfect active indicative 'pepalaiken' — a completed action with ongoing results — to say that by calling the covenant 'new,' God declared the first permanently obsolete, with no grammatical allowance for future reinstatement.
Was the land promise to Israel already fulfilled in the Old Testament?
Three Old Testament narrators explicitly declare it fulfilled using identical vocabulary: Joshua, Solomon, and the post-exilic Levites each state 'not one word fell' from all God promised — and Hebrews says the patriarchs themselves understood the promise pointed beyond physical territory.