Isaiah 40:8

the word of our God is the word spoken by the prophets to Israel, the announcement of Jehovah's immutable purpose in the world; this is the one permanent factor in human history. It is a mistake to limit the reference to the word of promise just declared by the prophet; the statement is general, although the implied argument is that as the threatening predictions of earlier prophets have been fulfilled, so this new word of comfort shall stand, because it proceeds from the same God, who can dissolve the mightiest combinations of human power (Isaiah 40:23).