Sir, there are many passages we can examine but the most compelling are from John and Paul. I think you know the passages from Paul on the warring of the flesh? A good one from the Gospels is when Jesus washes the feet of the disciples. He tells Peter they are already clean and just need their feet to be washed. I notice well it is Jesus doing the washing and not the disciples washing their own feet or each other's.
The best I think is what John said here:
1 John 2: My little children, these things I write to you, so that you may not sin. And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous. 2 And He Himself is the propitiation for our sins, and not for ours only but also for the whole world.
Tells me Jesus needs to be our Advocate in order for our sins to be forgiven...all of them---past, present and future. The remainder of this epistle tells us to live Godly lives and to reject evil. We do well to obey what is written.
Another "element" often omitted in some of these discussions? The Holy Spirit. Jesus Promised the Comfortor for all who believed in Him. So when a believer sins the Holy Spirit convicts the sinner to repent, thus bringing us back into fellowship with Him. Another great reference to look at is David's sin and Nathan's confrontation with him. Take a look at that encounter. Truly amazing this Grace.
There is no evidence in Scriptures of Grace coming and going, clinging and then dispensing and coming back again and repeating the cycle daily over and over. There is none of that. To claim Grace as "fleeting" would be denying the Power of God to regenerate the sinner into a new creature. It would deny the Power of God to convict his children of their errors and transgressions.
And more so: Since the Torah is engraved within, and since the type of the Temple is internalized inside of each and every one of us; we, as priests can go boldly into the Holy Place, before the altar of the heart; And that we, as priests have an eternal High Priest within the Temple who performs intercession for us, How then can ANY external mechanism have any effect whatsoever?
When we sin, it is the conviction of the Holy Ruach that makes us aware thereof, and the heartfelt sacrifice upon the altar of the heart that brings forgiveness. That is how the mechanism works.
And furthermore, when the Father puts one in our path who could benefit from our past trespasses, we are bound to witness to that brother, and tell where our own sins lead us, to better accommodate the conviction of the Ruach within HIM, thus turning our awful things into necessary and useful things... victory for the Kingdom! I cannot tell you how many times my testimony has been called for - The Father sending many into my path for the expressed and customized message that I can bring to the table!
This Protestant method is very effective, and WAY more powerful than a confession before some old man with a couple of hail marys to absolve the penitent!
We can dynamically and actively pastor each other, exhort each other, witness and testify, plead the truth and show the Scriptures, But no external source can intercede within the Temple.