A small person making a mistake will always embellish it, which means when a person of small character makes a mistake he won't try to change it for the better, but instead, he will try to cover it up and embellish it.
小人の過つやかならず文（かざ）る…小人物は過ちを犯してもそれを改めようとはしないで、つくろい飾ろうとする。