An ancient eldritch horror/diety says you have been chosen to be the sacrificial lamb, wether you agree to go or not decides humanities outcome. Do you go?

The diety said you will be in ceaseless agony and unending torment basically no one in the history of torture has been tortured with torture like the torture you'll be tortured with for all eternity just an unending cycle of pain beyond human comprehension. A single second on earth is a million years in your hell.

If you decide not to go humanity will suffer a slow collapse and cease to exist you will not die and you just live forever on a barren planet you could've saved. If you do decide to go humanity will prosper and advance for millenias to come, statues will be erected in your name songs will be sung about your sacrifice, a planet wide day of mourning and your name will forever be etched as humanities greatest human. Humanity will be forever grateful and in your debt. Who knows maybe one day humanity will be advance enough they'll attempt to break you out.