There appears various themes in the discussion here which the detail is making confused.
Jesus came to change us. He came to deciple us to make us perfect.
As people we are always looking at trying to define how to get there and how to show we have arrived.
Jesus critized the pharisees for compromise, for claiming the moral authority of Gods law but failing to deliver its reality.
There must be a real sense in which if we claim to be mature in Jesus, we need to know what walking in perfection means and how the law defines this. Now the law we are refering to is the moral law, the law of precepts and ideas that frame what is righteous behaviour.
In a very real way we cannot claim we have arrived and live far from this moral law. For likewise to claim we have Gods heart in us, yet continue to choose to sin, is actually to say this heart is worthless.
Now for me this reality is in the world of motivations, emotions, and seeing Jesus in the middle driving our lives forward. Now if some want to say they see the benchmark of helping us see issues aright are the moral law, fine. If people want to emphasis grace and forgiveness, fine, but both have to be able to show progress in people.
I will put this in context. A man can meet a beautiful woman who they get on well with and could easily have an affair. But which is the leading of God? The old marriage was a mistake and God is calling them out of it (invent an excuse) or is faithfullness and acknowledging biology and putting it in its place is the reality of the gospel. How we feel over one issue is always balanced with other feelings and loyalties. For me the power is love and sacrifice, seeing commitments and honesty, not wishing for a dream of "heaven" here, but realising we reap what we sow in each other, no matter how it might appear on the surface. The moral law helps me get focus, grace helps me overcome my failures, and love empowers victory through the cross. So what am I? Walking in Gods perfection?