'Vain words' in the Bible

Let there more work be laid upon the men, that they may labor in it; and let them not give regard to vain words.

You say, (but they are but vain words,) I have counsel and strength for the war. Now on whom do you trust, that you rebel against me?

Shall vain words have an end? or what emboldens you that you answer?

I say, you speak (but they are but vain words), I have counsel and strength for war: now on whom do you trust, that you rebel against me?

Let no man deceive you with vain words: for because of these things comes the wrath of God upon the children of disobedience.