'Worthless' in the Bible

"Look, O Lord! Consider that I have become worthless!"

(Nun) Your prophets saw visions for you that were worthless lies. They failed to expose your sin so as to restore your fortunes. They saw oracles for you that were worthless lies.

[And as for us,] yet our eyes failed,Looking in vain for help.Watching [from the towers] we watchedFor a nation that could not save.