A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
isa 26:1CONNECTED WITH THE TWENTY-FOURTH AND TWENTY-FIFTH CHAPTERS. SONG OF PRAISE OF ISRAEL AFTER BEING RESTORED TO THEIR OWN LAND. (Isa. 26:1-21)
strong city--Jerusalem, strong in Jehovah's protection: type of the new Jerusalem (Psa 48:1-3), contrasted with the overthrow of the ungodly foe (Isa 26:4-7, Isa 26:12-14; Rev 22:2, Rev 22:10-12, &c.).
salvation . . . walls-- (Isa 60:18; Jer 3:23; Zac 2:5). MAURER translates, "Jehovah makes His help serve as walls" (Isa 33:20-21, &c.).
bulwarks--the trench with the antemural earthworks exterior to the wall.
isa 26:2Address of the returning people to the gates of Jerusalem (type of the heavenly city, Heb 12:22); (Psa 24:7, Psa 24:9; Psa 118:19). Antitypically (Rev 22:14; Rev 21:25, Rev 21:27).
righteous nation--that had not apostatized during the captivity. HORSLEY translates, "The nation of the Just One," namely, the Jews.
isa 26:3mind . . . stayed-- (Psa 112:7-8). Jesus can create "perfect peace" within thy mind, though storms of trial rage without (Isa 57:19; Mar 4:39); as a city kept securely by a strong garrison within, though besieged without (so Phi 4:7). "Keep," literally, "guard as with a garrison." HORSLEY translates, (God's) workmanship (the Hebrew does not probably mean "mind," but "a thing formed," Eph 2:10), so constantly "supported"; or else "formed and supported (by Thee) Thou shalt preserve (it, namely, the righteous nation) in perpetual peace."
isa 26:4Lord JEHOVAH--Hebrew, Jah, Jehovah. The union of the two names expresses in the highest degree God's unchanging love and power (compare Psa 68:4). This passage, and Isa 12:2; Exo 6:3; Psa 83:18, are the four in which the English Version retains the JEHOVAH of the original. MAURER translates, "For JAH (the eternal unchangeable One, Exo 3:14) is JEHOVAH, the rock of ages" (compare Isa 45:17; Deu 32:15; Sa1 2:2).
isa 26:5lofty city--Babylon; representative of the stronghold of the foes of God's people in all ages (Isa 25:2, Isa 25:12; Isa 13:14).
isa 26:6poor-- (Isa 25:4), the once afflicted Jewish captives. "Foot shall tread," is figurative for exulting in the fall of God's enemies (Rev 18:20).
isa 26:7uprightness--rather, "is direct," that is, is directed by God to a prosperous issue, however many be their afflictions in the meantime (as in the case of the Jewish exiles); the context requires this sense (Psa 34:19; Pro 3:6; Pro 11:5), [MAURER]: thus "way" means God's dealings with the righteous (Psa 37:23).
most upright-- (Deu 32:4).
dost weigh-- (Sa1 2:3; Pro 5:21). Rather, "thou dost make plain and level" [MAURER], removing all obstacles (Isa 40:3-4).
isa 26:8way of thy judgments--We have waited for Thy proceeding to punish the enemy (Isa 26:9-10) [MAURER]. HORSLEY translates Isa 26:7-8, "The path of the Just One is perfectly even; an even road Thou wilt level for the Just One, even the path of Thy laws, O Jehovah. We have expected Thee."
name . . . remembrance--the manifested character of God by which He would be remembered (Isa 64:5; Exo 3:15).
isa 26:9With, . . . soul . . . I--literally, "I . . . my soul," in apposition; the faithful Jews here speak individually. The overthrow of the foe and the restoration of the Jews are to follow upon prayer on the part of the latter and of all God's people (Isa 62:1-4, Isa 62:6-7; Psa 102:13-17).
in the night-- (Psa 63:6; Sol 3:1).
world . . . learn . . . righteousness--the remnant left after judgments (Psa 58:10-11; Zac 14:16).
isa 26:10uprightness--rather, as in Isa 26:7, "prosperity," answering to "favor" in the parallelism, and in antithesis to "judgments in the earth" (Isa 26:9); where prosperity attends the wicked as well as the just, "he will not learn righteousness," therefore judgments must be sent that he may "learn" it [MAURER].
isa 26:11lifted up--to punish the foes of God's people. They who will not see shall be made to "see" to their cost (Isa 5:12).
their envy at the people--that is, "Thy people." LOWTH translates, "They shall see with confusion Thy zeal for Thy people."
fire of . . . enemies--that is, the fire to which Thine enemies are doomed (Isa 9:18).
isa 26:12peace--God's favor, including all blessings, temporal and spiritual, opposed to their previous trials (Psa 138:8).
isa 26:13other lords--temporal; heathen kings (Ch2 12:8; Ch2 28:5-6), Nebuchadnezzar, &c. Spiritual also, idols and lusts (Rom 6:16-18).
by thee only--It is due to Thee alone, that we again worship Thee as our Lord [MAURER]. "(We are) Thine only, we will celebrate Thy name" [HORSLEY]. The sanctifying effect of affliction (Psa 71:16; Psa 119:67, Psa 119:71).
isa 26:14They--The "other lords" or tyrants (Isa 26:13).
shall not live--namely, again.
deceased--Hebrew, "Rephaim"; powerless, in the land of shades (Isa 14:9-10).
therefore--that is, inasmuch as. Compare "therefore" (Gen 18:5; Gen 19:8).
isa 26:15hast--prophetical preterite (Isa 9:3).
hast removed . . . far . . . ends of . . . earth--rather, "Thou hast extended far all the borders of the land" [VITRINGA].
poured out-- (Psa 62:8), as a vessel emptying out all its contents.
prayer--literally, "a whispered prayer," Margin, "a secret sighing" to God for help (compare Jer 13:17; Deu 8:16).
isa 26:17An image of anguish accompanied with expectation, to be followed by joy that will cause the anguish utterly to be forgotten. Zion, looking for deliverance, seemingly in vain, but really about to be gloriously saved (Mic 4:9-13; Mic 5:1-3; Joh 16:21-22).
isa 26:18brought forth wind--MICHAELIS explains this of the disease empneumatosis. Rather, "wind" is a figure for that which proves an abortive effort. The "we" is in antithesis to "Thy," "my" (Isa 26:19), what we vainly attempt, God will accomplish.
not wrought . . . deliverance in . . . earth--literally, "the land (Judea) is not made security," that is, is not become a place of security from our enemies.
neither . . . world fallen--The "world" at large, is in antithesis to "the earth," that is, Judea. The world at enmity with the city of God has not been subdued. But MAURER explains "fallen," according to Arabic idiom, of the birth of a child, which is said to fall when being born; "inhabitants of the world (Israel, Isa 24:4; not the world in general) are not yet born"; that is, the country as yet lies desolate, and is not yet populated.
isa 26:19In antithesis to Isa 26:14, "They (Israel's foes) shall not live"; "Thy (Jehovah's) dead men (the Jews) shall live," that is, primarily, be restored, spiritually (Isa 54:1-3), civilly and nationally (Isa 26:15); whereas Thy foes shall not; ultimately, and in the fullest scope of the prophecy, restored to life literally (Eze 37:1-14; Dan 12:2).
together with my dead body--rather, "my dead body," or "bodies" (the Jewish nation personified, which had been spiritually and civilly dead; or the nation, as a parent, speaking of the bodies of her children individually, see on Isa 26:9, "I," "My"): Jehovah's "dead" and "my dead" are one and the same [HORSLEY]. However, as Jesus is the antitype to Israel (Mat 2:15), English Version gives a true sense, and one ultimately contemplated in the prophecy: Christ's dead body being raised again is the source of Jehovah's people (all, and especially believers, the spiritual Israelites) also being raised (Co1 15:20-22).
Awake-- (Eph 5:14), spiritually.
in dust--prostate and dead, spiritually and nationally; also literally (Isa 25:12; Isa 47:1).
dew--which falls copiously in the East and supplies somewhat the lack of rain (Hos 14:5).
cast out . . . dead--that is, shall bring them forth to life again.
isa 26:20enter . . . chambers--When God is about to take vengeance on the ungodly, the saints shall be shut in by Him in a place of safety, as Noah and his family were in the days of the flood (Gen 7:16), and as Israel was commanded not to go out of doors on the night of the slaying of the Egyptian first-born (Exo 12:22-23; Psa 31:20; Psa 83:3). The saints are calmly and confidently to await the issue (Exo 14:13-14).
isa 26:21(Mic 1:3; Jde 1:14).
disclose . . . blood-- (Gen 4:10-11; Job 16:18; Eze 24:7-8). All the innocent blood shed, and all other wrongs done, so long seemingly with impunity, shall then be avenged (Rev 16:6).
At the time when Israel shall be delivered, and the ungodly nations punished, God shall punish also the great enemy of the Church.