Both Jacob and Israel are mentioned in v. 8. The message of chs. 9:8 to 10:4 is primarily directed against the rebellious ten tribes, usually addressed as Ephraim or Samaria (ch. 9:9, 21). But in v. 14 the term “Israel” almost certainly refers to the northern nation. Does Israel in v. 8 refer to the northern nation, Israel, and Jacob, to Judah? If so, the meaning is that the Lord sent this message through Judah to Israel.

 However, in a more general sense Isaiah often uses the terms Jacob and Israel for all God’s chosen people (see chs. 10:20-22; 27:6; 29:23; 40:27; 41:8, 14; 43:1, 22, 28; 44:5; 46:3; 48:1, 12; 49:6). After the final fall of the northern kingdom both terms generally refer to Judah.

 As the context (vs. 9-17) makes clear, the following message was “against Jacob” in the sense that it presaged divine judgment. This verse begins a new section, extending through ch. 10:4, in which the Lord administers a rebuke to the nation of Israel. The vision of the King who will reign in glory has ended, and the prophet turns his attention to the problems of the immediate situation. The time is the same as that of the previous chapters, for Rezin of Syria is still alive (v. 11), and the message must therefore have been delivered between 735 and 732, when Rezin died.