Isaiah 40:8

“The grass withereth, the flower fadeth, &c.] Which is repeated, to raise attention to it, as being a matter of importance, and for the confirmation of it: but the word of our God shall stand for ever; the Apostle Peter adds, by way of explanation, and this is the word, which by the Gospel is preached unto you; who seems to distinguish the word from the Gospel, by which it is preached, and to intend Christ the essential Word; who stands or abides for ever as a divine Person; in his office as Mediator, being Prophet, Priest, and King for ever; in the efficacy of his blood, righteousness, and sacrifice; and in the fulness of his grace: it is true of the written word or Gospel, which remains, is…”

“The grass withereth ... - This is repeated from the former verse for the sake of emphasis, or strong confirmation. But the word of our God - The phrase ‘word of our God,’ refers either to his promise to be the protector and deliverer of his people in their captivity, or, in general, means that all his promises shall be firm and unchanging. Shall stand for ever - Amidst all revolutions among men, his promise shall be firm. It shall not only live amidst the changes of dynasties, and the revolutions of empires, but it shall continue forever and ever. This is designed for support to an afflicted and oppressed people; and it must have been to them, in their bondage, the source of high…”

“40:8 the word of our God stands forever: All of God’s words (his plans as well as the written word) will succeed. God might frustrate human expectations, but everything will happen according to his wise plan (see 14:24; 55:8-11; see also Matt 25:34).”

“the word: Isa 46:10, Isa 46:11, Isa 55:10, Isa 55:11; Psa 119:89-91; Zac 1:6; Mat 5:18, Mat 24:35; Mar 13:31; Joh 10:35, Joh 12:34; Rom 3:1-3; Pe1 1:25 Isaiah 40:9”