en_tn/isa/40/27.md

Why do you say, Jacob and declare, Israel

This says the same thing twice for emphasis. AT: "Why do you say, O people of Israel." Isaiah uses a question for emphasis. AT: "You should not say, O people of Israel" (See: rc://en/ta/man/translate/figs-doublet and rc://en/ta/man/translate/figs-rquestion)

My way is hidden from Yahweh, and my God is not concerned about my vindication

"Yahweh does not see us. He is not concerned to clear our blame"

Have you not known? Have you not heard?

See how you translated this in Isaiah 40:21.