Isaiah 48:18

O that thou hadst hearkened &c. This is the strict rendering of the Hebr. idiom, which properly expresses a wish that has not been realised (see Driver, Tenses, § 140). It may, indeed (as in ch. Isaiah 64:1), be used in an impassioned wish for the future, and many commentators prefer that sense here, "O that thou wouldst hearken" (see Davidson, Syntax, § 134). So R.V. marg. But the construction in Isaiah 64:1 is exceptional, and the two cases are not strictly parallel. Here the reference to the past is strengthened by the following clauses: "then had thy peace been" &c. (consec. impf.); and it is only a feeling of the unsuitability of the idea to the discourse that could ever suggest a departure from the ordinary rule of syntax. It is true that "such a retrospect here at the close would be extraordinary" (Dillmann), but in reality a hypothetical promise of future blessedness would be just as surprising. The difficulty is not grammatical but critical.

peacemeans national prosperity, "welfare," as explained in the next verse (cf. ch. Isaiah 66:12); righteousnessis used in the same sense as in ch. Isaiah 45:8.

as a river i.e. a perennial stream, such as the Euphrates (cf. Amos 5:24). It is easy to understand the impression made on the mind of a native of Palestine, accustomed to "deceitful brooks" that run dry in the summer, by the sight of a great river, flowing on for ever in undiminished volume. The actual history of Israel had been like the wadisof Judæa, transient gleams of prosperity being interrupted by long intervals of misfortune; the river suggests to the writer an image of the boundless and unfailing blessedness which would have followed the keeping of the Divine commandments.

the waves of the sea cf. ch. Isaiah 11:9.