'Vain words' in the Bible

Let more work be laid upon the men, that they may labor therein: and let them not regard vain words.

Thou sayest, but they are but vain words, I have counsel and strength for the war. Now in whom dost thou trust, that thou rebellest against me?

Shall vain words have an end? or what emboldeneth thee that thou answerest?

I say, sayest thou (but they are but vain words) I have counsel and strength for war: now on whom dost thou trust, that thou rebellest against me?

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