Who declared, "I know that my Redeemer lives"?

Answer: Job

In the midst of his suffering Job declared that his Redeemer lives and that in his flesh he would see God.

“But I know that my Redeemer lives, and in the end He will stand upon the earth. Even after my skin has been destroyed, yet in my flesh I will see God.”— Job 19:25-26 (BSB)