The Scofield Bible Commentary, by Cyrus Ingerson Scofield, [1917], at sacred-texts.com
servant
There is a twofold account of the Coming Servant:
(1) he is represented as weak, despised, rejected, slain:
(2) and also as a mighty conqueror, taking vengeance on the nations and restoring Israel (for example (Isa 40:10); (Isa 63:1-4). The former class of passages relate to the first advent, and are fulfilled; the latter to the second advent, and are unfulfilled.
for a light of the Gentiles
The prophets connect the Gentiles with Christ in a threefold way"
(1) as the Light He brings salvation to the Gentiles (Luk 2:32); (Act 13:47); (Act 13:48).
(2) as the "Root of Jesse" He is to reign over the Gentiles in His kingdom. (Isa 11:10); (Rom 15:12). He saves the Gentiles, which is the distinctive feature of this present age. (Rom 11:17-24); (Eph 2:11); (Eph 2:12) He reigns over the Gentiles in the kingdom-age, to follow this.
See "Kingdom (Old Testament),"
(Gen 1:26-28); (Zac 12:8).
(3) Believing Gentiles in the present age, together with believing Jews, constitute "the church which is His body."
(See Scofield) - (Eph 3:6).
former things
That is, Isaiah's prediction of Sennacherib's invasion and its results, Isaiah 10 and 37. See also, (Isa 41:21-23); (Isa 43:8-12); (Isa 44:7); (Isa 48:3); (Isa 48:5); (Isa 48:16). This appeal of the prophet to the fulfilment of his former predictions strongly confirms the unity of the book.