Q: Will we be sad in heaven about people in hell? No — because of resolution, not memory loss. "Former things not remembered" means not dwelling on them or worrying, not literal amnesia. In God's presence with his perspective, we'll understand his justice is right. The glory will outshine all grief.

The OT phrase "not brought to remembrance" means not dwelling on it, not memory wipe — God "forgetting" sin doesn't mean literal amnesia. In God's presence, we'll see from his perspective and understand hell is just. Like seeing full context behind a police use of force that initially looked like abuse. The glory of God's presence outshines all grief.