Brant, Michael and I belong to a school of thought that sees covenant as a central concept in biblical theology, particularly Catholic biblical theology. Such an approach has strong support in the text of Scripture and in the tradition and liturgy of the Church, and would seem to be a "no-brainer," yet there are those who oppose it and de-emphasize the significance of covenant for interpreting the Scriptures in the Church. For that reason, it's necessary periodically to justify this approach.
When I teach biblical theology, I focus on a series of covenants which are central to the economy of salvation: the (1) Creation (or Adamic; Genesis 1-3; Hosea 6:7), (2) Noahic (David Noel Freedman preferred "Noachian"; Genesis 9), (3) Abrahamic (Genesis 15, 17, 22); (4) Mosaic (Exodus 24), (5) Davidic (2 Samuel 7; Psalm 89); and (6) New (Jeremiah 31:31; Luke 22:20). (Of course, I learned this from others and nothing about it is unique to me.) It has always struck me, and my students, how well this overview of the divine economy accords with the readings of the lectionary of the Mass, especially the readings of the Easter Vigil.
I'll proceed to point out how all these covenants appear in various forms in the seven Old Testament readings that form the backbone of the Liturgy of the Word for the Vigil.
The readings begin with the creation story from Genesis 1, a text concerning the Creation Covenant. That there was a covenant present at creation is controversial, but it has the backing of Popes John Paul II and Benedict XVI, as well as certain contemporary scholars and a stream of the Jewish tradition. Benedict XVI's argument for the presence of a creation covenant hinges on the culmination of the creation week with the Sabbath, which elsewhere in the OT is understood to be the sign of the covenant (Exod 31:16-17). Hosea 6:7 (in Hebrew: "Like Adam they transgressed the covenant") testifies to a very early interpretive tradition which understood a covenant to be present already at the beginning of human history.
The second OT reading is Genesis 22, one of the most central texts in all the Old Testament. I call it the "Calvary of the Old Testament," perhaps the most important type of Christ's sacrifice on the cross in the pages of the Scriptures of Israel. Genesis 22, of course, recounts the "Aqedah" or binding of Isaac, in which Abraham comes close to sacrificing his "one and only" or "only begotten" son on the wood of the altar on the top of Mt. Moriah. God's solemn oath of blessing on Abraham in vv. 15-18 is one of the central texts in all the Bible: arguably, this the culmination of the covenant with Abraham begun in Genesis 15 and continued in Genesis 17. Although the word "covenant" does not appear in Genesis 22, God's solemn oath in vv. 15-18 was understood as a covenant in subsequent Scripture (e.g. Deut 7:8-9; Luke 1:72-73). This solemn covenant-oath by God promises blessing to all nations through the seed of Abraham; Easter is a celebration of the fulfillment of that promise, as all nations have been blessed through Jesus the seed of Abraham (Matt 1:1) who pours out the Spirit on all nations through his self-sacrifice on the cross.
The third OT reading for the Vigil is Exodus 14, the account of the triumph of God in delivering the Israelites from the armies of Egypt at the Red Sea. This corresponds to the Mosaic Covenant (the covenant with Israel through Moses), as the people of Israel had already entered into a covenant relationship with God through the Passover (Exodus 12-13) and were headed out to Sinai where the covenant would be further solemnized (Exodus 24).
The fourth OT reading is a beautiful passage from Isaiah 54:5-14, which, surprisingly, makes reference to the Noahic Covenant (Isaiah 54:9), and compares the coming “covenant of peace” (Isaiah’s term for the reality described by Jeremiah as the “new covenant,” Jer 31:31) to the covenant made with Noah. This passage also employs touching marital imagery to describe God’s relationship with Israel. Marriage was a form of covenant in ancient Israel, so it was natural to describe God’s covenant relationship with Israel in terms of marriage.
The fifth OT reading (Isaiah 55:1-11) is one of my favorite, and one of the most amazing, texts from Isaiah. In this passage, God promises that at some point in the future, he will offer the covenant of David (“I will make with you an everlasting covenant, my covenant fidelity [Hebrew hesed] for David”; Isa 55:3) to every one who is hungry and thirsty. He will offer this covenant through eating and drinking (Isa 55:1)!
The sixth OT focuses on divine wisdom, but the seventh and last (Ezek 36:16-28) has important covenant themes. After recounting Israel’s unfaithfulness to the (Mosaic) covenant, Ezekiel prophesies a coming day when God will sprinkle his people with water and put a new spirit within them which will enable them to keep their covenant with God (“live by my statutes, careful to observe my decrees”). Ezekiel 36 is found canonically in the middle of Ezekiel’s “Book of Consolation” (Ezek 34-37), a long section of Ezekiel in which the prophet offers hope for a new age for Israel, a hope that culminates in Ezek 37:25-28 with the establishment of a “covenant of peace”, an “everlasting covenant” (37:26), Ezekiel’s terms for Jeremiah’s “new covenant” (Jer 31:31).
Thus, all the major covenants of salvation history are referred to in some form in the seven OT readings for the Easter Vigil, and taken together the readings (not to mention the psalms that go with them!) make a beautiful synopsis of the general structure of the divine economy (salvation history). Since the Vigil, like every mass, culminates in the consecration of the bread and wine which become “the New and Everlasting Covenant” in Christ’s blood, it is appropriate that the OT readings recount the older and provisional covenants that anticipated the new one celebrated in the Liturgy. Understanding salvation history through the lens of the covenant is an authentically Catholic approach to biblical theology.