And when they shall say— Here follows the address of the prophet to the Jewish nation, drawn from the argument of the preceding prophesy,—to the first verse of the 9th chapter; and then a remarkable illustration of the prophesy concerning Jehovah the teacher, who was hereafter to appear to the Jews,—from Isaiah 8:2-7. The connection is this: the prophet having foretold the coming of the Messiah, and the disciples which he would have, takes this occasion of addressing the Jews, and reminding them of their duty, as he had done, ch. Isaiah 2:6 compared with Isaiah 8:1-2 where he first delivers that memorable prophesy concerning Jehovah, or Messiah, the teacher. He saw the nation in his time most propense to foreign superstitions, particularly to the divinations, soothsayings, and astrology of the Syrians, Egyptians, &c. ch. Isaiah 2:6 but not regarding the pure instructions of God as they ought: he therefore warns them against placing any dependance on such follies and absurdities, and exhorts them to disregard all merely human teaching and assistance, while they applied solely to the divine law and testimony. See Vitringa. Instead of it is because, &c. Isaiah 8:20 we may read, whoever it be, to him shall there be no morning: that is to say, "Upon them Christ, the light of the world, shall not arise." See Hosea, ch. Isaiah 6:1.
Related Commentaries of Isaiah 8:19
Isaiah 8:19-20
19 And when they shall say unto you, Seek unto them that have familiar spirits, and unto wizards that peep, and that mutter: should not a people seek unto their God? for the living to the dead?
20 To the law and to the testimony: if they speak not according to this word,d it is because there is no light in them.