The Hebrew word muna, translated as truth
has the same meaning as in Jeremiah 5:1, Jeremiah 5:3. It means faithfulness and, in this context, faithfulness to the covenant and to the Lord. This kind of faithfulness has perished
in Judah; it is cut off from their lips.
1 By referring to Judah as the nation,
the Lord is probably showing that they no longer have their special status as his people and have become like all the other nations.2
28 And you shall say to them, ‘This is the nation that did not obey the voice of the LORD their God, and did not accept discipline; truth has perished; it is cut off from their lips.