For two reasons, Isaiah 2:5 should be taken as the introduction to what follows, rather than as the conclusion to 2:1-4.

First, the exhortation of v. 5 is to walk in the “light” of Yahweh, and the following passage refers to the “splendor” of Yahweh (vv. 10, 19, 21), as well as to the light-full “day” of Yahweh (v. 12).

Second, the name “Yahweh” appears seven times in verses 5-22 (vv. 5, 10, 11, 12, 17, 19, 21).  Without verse 5, there would not be a sevenfold reference to Yahweh in this “sabbatical” judgment/day of Yahweh passage.  Yahweh is also used seven times in the opening section (1:1-20).