The source of Jacob’s interpretation of the above Isaiah prophecy is a vision and an explanation given by an angel (vv. 8–11). We have no account of this vision, but the angel apparently was a part of the vision. The prophecy, now mostly history, outlines the destiny of the nation of Judah. The Jews would be slain and carried captive into Babylon (v. 8). The traditional dating of this captivity is 607–538 B.C., fulfilling the prophecy of Jeremiah that this whole land would “serve the king of Babylon seventy years” (Jeremiah 25:11–12). After the seventy years, Cyrus king of Persia, the new world power, issued a proclamation for the Jews to return to Jerusalem as Jacob was shown (v. 9).
1 Now in the first year of Cyrus king of Persia, that the word of the Lord by the mouth of Jeremiah might be fulfilled, the Lord stirred up the spirit of Cyrus king of Persia, that he made a proclamation throughout all his kingdom, and put it also in writing, saying,
32 Thus saith Cyrus king of Persia, The Lord God of heaven hath given me all the kingdoms of the earth; and he hath charged me to build him a house at Jerusalem, which is in Judah.
33 Who is there among you of all his people? his God be with him, and let him go up to Jerusalem, which is Judah, and build the house of the Lord God of Israel, (he is the God,) which is in Jerusalem. [Ezra 1:1–3]
As also shown to Jacob, the Holy One of Israel did manifest himself unto the Jews in the flesh (v. 9). He was born, ministered to them, and was crucified (A.D. 1–34, Book of Mormon dating). The Judgments of the Holy One of Israel then came upon them (v. 10). The Roman Conquest came in A.D.70, and the Jews were scattered, smitten, and hated (after A.D. 70). The angel told Jacob that when the Jews come to the knowledge of their Redeemer, they would be gathered again in the latter days (v. 11).
Jacob also comments concerning the Gentiles spoken of in the prophecy of Isaiah. Nephi spoke of those in America (1 Nephi 22). Jacob spoke of those of whom the Jews were among. He doesn’t identify the locality, but it was apparently basically in Europe where the Jews were scattered. It would also include all the other areas of the diaspora. Jacob’s main concern is for those who will be saved, indicating an opportunity to receive the gospel. Part of the covenant made to Abraham was to bless all nations (Gentiles) (1 Nephi 22:9). Those who wait for the Messiah, whether Jew or Gentile, will be saved (v. 12). Those who unite with the great and abominable church and fight against Zion will not (v. 13). This part of the prophecy is still in the future.