Jesus said “Go, and from now on do not sin any more.” He did not say “Go forth and try your best.” or even “Go forth knowing you probably will sin, but that’s ok.” That’s part of something we miss in confession… it’s that firm resolution of purpose. We are supposed to go forth intending never to sin again. When we fall, we know there are things we can do to be forgiven… because God is merciful. But we should never take that for granted, we should never ‘presume.’ The sin of presumption is sinning knowing that God will forgive you, so you go ahead and do it.
This is an example of reconciliation in that story from scripture. In confession we are repentant. We aren’t supposed to live there thinking “Well I’ll see you in a week when I do it again.” We are supposed to leave there instead intending to never do that again, to not need confession again… to do our best, work our hardest, to be the man/woman that God created us to be. That’s what Jesus meant here.
It’s kind of like the whole concept of aiming for purgatory… you should never aim for that… you should aim for heaven… we know that God is merciful, but our goal is to be a Saint… not aim for less than that bar of perfection.