I was the first to tell Zion: ‘Look, here they are!’ And I gave to Jerusalem a herald of good news.
27. The first to Zion. “I, saith Jehovah, am the first that has foretold by my prophets to the Jews those things which none of the false gods, and none of their prophets could foretell, the destruction of Babylon and the return of the banished Jews into their native country.” — Rosenmuller.
The Lord, by the prophet, here repeats the challenge to idolaters to make out the pretentions of their idols: "Produce your cause (Isa 41:21) and make your best of it; bring forth the strongest reasons you have to prove that your idols are gods, and worthy of your adoration." Note, There needs no more to show the absurdity of sin than to produce the reasons...
Commenting on Isaiah 41:21-29
The first shall say to Zion, behold, behold them,.... Or, "I the first say to Zion"; I who am the first and the last, Isa 41:4 which some ancient Jewish writers (d) observe is the name of the Messiah, and apply the passage to him; or, I am the "first" that say these things to Zion (e), behold, behold them; behold such and such things...