“For whoever keeps the whole law and yet stumbles at just one point is guilty of breaking all of it.” James 2:10
The Word of God is more like a glass window than it is like a pile of rocks. Suppose I find a large pile of rocks. It is a big pile with many hundreds of rocks in it. There I find one rock I do not like. I don’t like its color or its shape. So I go, take the rock out of the pile and throw it away as far as I can. I think, “Now it looks better. No one will miss that one stone.”
Now imagine a window. I take a stone and strike the glass. A crack develops and spreads through the whole window and destroys it completely. I cannot treat the window like a pile of rocks. The Word of God is like a window. We must take all of it, not just some part. If we break one part, we have broken the whole. So then if I practice favoritism, I have broken the entirety of the Law.