The theme of this passage is simply the words that we say and how it really reflects our heart. Out of the abundance of the heart, the mouth speaks. Just as our works given evidence to being new creatures in Christ, so do our words reflect the change that has taken place. Our words are powerful; God's words were powerful first. An important question to ask ourselves - is what I am saying/speaking consistent with who I am in Christ Jesus and does it reflect our new heart and our new spirit. Only God came tame the tongue but we are called go seek his help and then his forgiveness when we fail. And, may the meditations of our heart and the words of our mouth be pleasing in your sight, Oh Lord our rock and our redeemer.