en_tn_condensed/jer/05/02.md

Although they say

The word "they" refers to the people of Jerusalem.

As Yahweh lives

"as surely as Yahweh is alive." The people use this expression to show that what they say next is certainly true. This is a way of making a solemn promise. See how you translated this in Jeremiah 4:2. Alternate translation: "I solemnly swear" (See: rc://en/ta/man/translate/figs-idiom)