Actually read all of 1 John. Chapter 1 will show you your state, if a person thinks they can “Sin no more.”
The “sin” in the quote is a reference by Jesus to a SPECIFIC sin (that aside if the advice comes from the Saviour it MUST be good and practicable or do you know better than Jesus?). Thus you prove my point. You've got to lose your loathing and ego when you pick up your Bible. I'm serious. I'm not being a wiseass; you SEE what you WANT to see.