Now let us see what the word impeccability means. Impeccability means "without sin." Impeccable comes from the Latin pecatus, which means "sin." The im in impeccable means "without," so impeccable means "without sin." Religions talk about sin and sinners, but let's understand what it really means to sin. A sin is anything that you do which goes against yourself. Everything you feel or believe or say that goes against yourself is sin. You go against yourself when you judge or blame yourself for anything. Being without sin is exactly the opposite. Being impeccable is not going against yourself. When you are impeccable, you take responsibility for your actions, but you do not judge or blame yourself.
From this point of view, the whole concept of sin changes from something moral or religious to something commonsense. Sin begins with rejections of yourself. Self-rejection is the biggest sin that you commit. In religious terms self-rejection is a "mortal sin," which leads to death. Impeccability, on the other hand, leads to life.
Don Miguel Ruiz (1997) The Four Agreements: A Practical Guide to Person Freedom (p. 31) Amber-Allen Publishing, Inc., San Rafael, CA 94903 (ISBN 1-878424-31-9)