# They will ask
The word "They" refers to the people of Israel or the people of Judah who are returning from Babylon to Jerusalem.
# join ourselves to Yahweh
This is figurative language used to explain a spiritual connection to Yahweh. (See: [[rc://en/ta/man/jit/figs-idiom]])
# that will not be forgotten
This states that the covenant will be obeyed forever. It can be stated in active form. Alternate translation: "that no one will forget" (See: [[rc://en/ta/man/jit/figs-activepassive]])