[N. B. -- The following post uses the terms Deutero-Isaiah (DI) and Trito-Isaiah (TI) as labels for the major sections of the Book of Isaiah. DI = Isa. 40-55. TI = Isa. 56-66. They should not be taken to imply any conclusions about the overall authorship and composition of the Book of Isaiah.]
For my class on Isaiah 40-66, I spent some time contemplating the theme of the "Wealth of the Nations" in the Book of Isaiah. This is my class presentation with a few additional observations.
The theme of the wealth of the nations appears primarily in Trito-Isaiah in an eschatological context concentrated in chs. 60-61 & 66. When the ultimate redemption of Israel is accomplished, the glory of YHWH will dwell in Zion visibly as a light (60:1-2) so bright that it removes the need for the sun and moon (60:19-20) and draws the nations en masse (60:3) like moths to a porch light (or a bug zapper if we recall the deadly power of the presence of YHWH). The nations all bring their wealth to YHWH as they experience this inexorable draw to the light (60:5-6, 11). In addition to bringing their wealth, the nations are bringing the children of Israel back (60:4). Israel has special status in this new age as a priestly class (61:6), and they and the temple appear to be the primary beneficiaries of the material tribute from the nations (60:7,13; 66:12, 18-20).
There is some ambiguity about whether the treasures spoken of in ch. 60 are literal or whether they refer metaphorically to Israel. Isa 60:4 refers to the Israelites being returned by the nations.
Isa 60:5 records Zion’s reaction:
Then you will see and shine. Your heart will be in awe and grow wide because the multitude of the sea has (re)turned to you, the wealth of the nations will come to you. (writer's translation)
The reference to the sea could possibly be understood in context of YHWH’s promise to Abraham in Gen. 22:17 to multiply his offspring more than the sand of the sea. So, Israel equals the multitude of the sea equals the wealth of nations. Perhaps both understandings are intended because the passage continues to speak of both wealth and children being brought to Zion (esp. 60:9-11).
Trito-Isaiah appears to be developing an idea from Deutero-Isaiah in 45:14 where YHWH promises that Egypt, Cush, and the Sabeans will place themselves under Israel’s sovereignty, recognizing that YHWH is the only God. They will bring their wealth and their merchandise with them. DI uses different terms for the products/wealth than TI. The theme appears in First Isaiah in 10:14 using words similar to those in TI, so it is possible that TI is reversing a concept from FI. In Isa. 10, YHWH is depicted punishing the nations and gathering their wealth as a consequence.
So, the wealth of the nations appears in two ways in Isaiah -- either as spoil resulting from conquest (Isa. 10) or as tribute willingly brought to YHWH at Zion (Isa. 45, 60-61, 66). The eschatological focus of the last part of Isaiah results in the second -- wealth as tribute -- being more prominent.
List of Relevant Passages in Isaiah
10:14; 45:14; 60:5-13; 61:6; 66:12, 18-20