Who is Isaiah and why is he important in the Old Testament?

Answer 1

He is very important as he foretold the birth of christ and also his trial , seven hundred years earlier.

Jewish Answer

Isaiah wasn't the most important prophet. As it's specified in the Tanach (Jewish Bible), Moses was the greatest of all prophets both past and future.

Answer 2

Yeshayahu (Isaiah) was a major prophet in the middle of the First Temple era, some 26 centuries ago, at the time of Uziah and the subsequent kings. His importance is (at least partly) because he was a pillar of righteousness in his own time, and a stronghold of succor, belief and hope for all later generations.

Answer 3

Isaiah foretold the birth of Christ , the trial , all 700 years earlier.