Whoever restrains his words has knowledge,
and he who has a cool spirit is a man of understanding.
Our words give away what is in our hearts, and the benefit of God's wisdom is most often known in our control of the tongue. The character of wisdom conveyed in this proverb is self control. And that is not an easy virtue to attain when it comes to the heat of conversation. In the "click to reply" fast-paced word of social media, restrained words are few, and there is no emoticon for silence.
The way this proverb amplifies self-control is instructive. It starts with our words, but is maintained by a "cool spirit". So the key to wise speech is a heart not wildly given to responding with emotional mood swing speeches. It would seem that "venting" or "speaking my mind" is thus a very bad idea.
Since self control is the better part of wisdom according to this proverb, I will seek that. I am naturally a very foolish sinner spouting all kinds of sinful nonsense. I need God's grace and Holy Spirit to help me restrain my foolish heart from pouring over my lips, or dripping across my keyboard. And so I will seek the discipline of God's truth to guide my thoughts and thus purposefully restrain my heart and words, so that God's wisdom can rule in my soul.