The word despise, Hebrew bzh, is an onomatopoeia, that means is sounds like what it does. When you say that group of letters is sounds like you are spitting something out of your mouth, bzzzah. You despise it, you want it away from you as quick as you can. Think of the last time you tasted something disgusting, like really sour milk, what was your visceral reaction, you probably spit it out. That is the force of this word. Nathan said David’s sin was bzh, despising the Word of God and God as disgusting. David got it immediately, his repentance was immediate. We get Psalm 51 from the experience. We also get a clear picture of what our sin really is and a model of our only appropriate response when we are confronted with it.
Not easy, but appropriate.