Jesus tells us in Matthew 12:37 that "by our words, the words that we speak out of our mouths, we shall be justified, and by our words we shall be condemned." So it's very important that we know the source of our words.
In order for us to speak God's words, we have to know what His words are. Written in the Scriptures, the Book of Proverbs is a good place to study about "words". We have to learn to speak good words, positive and uplifting words.
Cast down words that you feel like saying, and bring them into the obedience of the anointing ... words of doubt and unbeleif, negative words, words that try to place themselves above God's words. (2 Corinthians 10:4)
Mary C. Butler