Is sloppiness in speech caused by ignorance or apathy? I don’t know and I don’t care. —WILLIAM SAFIRE
Note: "Is sloppiness in speech caused by ignorance or apathy? I don't know and I don't care."
This means that we are to consciously hold back speech that will be harmful.
My words reflect my thoughts, my thoughts reflect my beliefs, and my beliefs, especially the unexamined ones, run my world.
For example, if I tell myself through my thoughts that I am worthless, I will begin to act that way, and others will treat me as if that were the truth.