Imagine you're thirsty and I offer you a glass of water; you would drink that right? But only if that water was clean. If I add even a single ounce of raw sewage to your otherwise crystal clear water, you'd refuse it. You'd treat a gallon of water with an ounce of sewage the same as you'd treat a gallon of sewage with an ounce of water - undrinkable.
The same concept applies to truth. Even the tiniest lie taints it. Truth only exists as a whole, not in part. Just the same as there's no such thing as being a little bit pregnant, there's no such thing as a half-truth - a half-truth is a whole-lie.
The same concept applies to sin. Even the tiniest one taints us. Perfection only exists as a whole, not in part. And we cannot achieve that on our own. It's in our nature as humans to desire it even though it is unattainable; much as we desire flight though we have no wings. We are not, and can never hope to be, perfect through our own abilities. We each are in need of a Savior. Ain't that the truth.