1. On that day. Some take this verse to be the conclusion of the last prophecy in the previous chapter. Given its strikingly mythological character, however, it could be an independent fragment.

Leviathan the slippery serpent. The Hebrew epithet bariaḥ is not certain in meaning. It could derive from the verbal stem that means “to flee,” hence “slippery.” It is also the ordinary word for the bolt of a gate and so could conceivably refer to the serpent held under lock and key. The entire line invokes the Canaanite cosmogonic myth of Leviathan as the primordial sea monster that the weather god Baal must subdue in order for dry land, safe from the raging sea, to come into being.

2. a lovely vineyard. This Song of the Vineyard is akin to the Parable of the Vineyard in chapter 5; in both cases, the vineyard is the people of Israel.

4. Should one give Me thorns and thistles. That is, if the people through its actions allow the vineyard to fall into ruins, God will burn out the noxious growths.

5. If he clings to My stronghold. The “he” would refer collectively to the people, and clinging to God’s stronghold means keeping faith with Him. The result is peace with God instead of the battle mentioned in verse 4.

6. In days to come. The Hebrew says merely “coming” in the plural, but it is likely that “days” was inadvertently dropped from the text. This phrase is usually an introductory formula for a prophecy, which would make this verse a fragment, although it might also be taken as the conclusion of the prophecy that begins in verse 2.

8. In due measure. The Hebrew besa’sa’h is anomalous and its meaning is uncertain. This translation follows the Targum in relating it to seʾah, a dry measure.

He drove her out. Though it may be disconcerting to the English reader, the Hebrew slides readily from referring to the Israelites as a collective “he” (verse 7) to a feminine pronominal suffix here (because the nation is often imagined symbolically as a woman).

east-wind day. The east wind blowing from the desert generally signals disaster.

9. all this comes. More literally, “all the fruit of.”

the altar. As the third verset of this line makes clear, this is an altar dedicated to pagan worship, which therefore has to be shattered.

10. gnaws away its boughs. The boughs are a metonymy for the deserted town. Now women foraging for fuel (verse 11) come to pick up the dry broken branches to use as kindling.

11. for they are not a discerning people. In consonance with a recurrent pattern in triadic lines, this third verset breaks away from the semantic parallelism and instead provides an explanatory summary not only of the whole line but of the whole prophecy: this disaster has befallen the people because of its failure to see and understand God’s ways.

12. And it shall be on that day. Once again, this formula signals the beginning of a new prophecy, one of national restoration and the punishment of Israel’s enemies.

from the stream of the Euphrates to Egypt’s river. Assyria and Egypt were the two great imperial powers between which the kingdom of Judah was caught in Isaiah’s time, the eighth century B.C.E.

13. a great ram’s horn shall sound. The ram’s horn was blown at coronations and to announce the jubilee year: here it inaugurates a grand period of renewal after national tribulations. Traditional interpreters associated this verse with the messianic age.

and those lost in the land of Assyria. The Hebrew verb equally means “to be lost” and “to perish.” It is distinctly possible that Isaiah, writing a century after the destruction of the northern kingdom of Israel and the exile of much of its population to Assyria, has that historical catastrophe in mind.