en_tn/jer/32/44.md

write in sealed scrolls. They will assemble witnesses

The "sealed scrolls" are the deeds that a person would sign to purchase land. Other people would be witnesses to confirm the purchase.

this is Yahweh's declaration

Yahweh speaks of himself by name to express the certainty of what he is declaring. See how you translated this in Jeremiah 1:8. Alternate translation: "this is what Yahweh has declared" or "this is what I, Yahweh, have declared" (See: rc://en/ta/man/translate/figs-123person)