This is an understatement: it is possible to strive for holiness while simultaneously recognizing one's limitations.
Put more precisely: we cannot be sanctified apart from the practice of humility--a true estimation that, yes, 79 months and 3 days from now, if I am still alive, I will still sin and have cause to say, "What a wretch I am and what a wonderful Savior we have!"
The realistic evaluation of one's incapacity to perfectly follow Jesus forms a foundation that can never be jettisoned if we are to build a life-house that lasts. It is only when I see how utterly dependent on Jesus I am that I can “leave the sin that so easily entangles.” Remember: the process of sanctification is coterminous with the practice of simple, childlike trust--expressed as understood need.
There is a mystery that shall likely remain untangled this side of eternity: it is only when we realize that we stand in need of forgiveness (yes, really!) each and every day that we can move beyond the experience of “mere” forgiveness. We are all Oedipus: the day you think you need no forgiveness is a day of blindness and exile, for that day is a day riddled with hubris. The gods know better.