Please read my previous post in this thread if you haven’t already:
https://christianchat.com/threads/dropping-this-nugget-on-forgiveness.197334/post-4488203
The suggestion is rather that we don’t have to ask for forgiveness because we are already forgiven. This does not negate the benefit of transparency before God (such as confessing a struggle and getting to the root of the sin with the Lord).
Scripture similarly says that if Jesus didn’t raise from the dead, our faith is vain. It is to no effect. If Jesus’ sacrifice was to pay the penalty for all sin (and grant remission; which it did), then there is no need to ask for forgiveness for the sin, judicially, otherwise nothing was gained in His death and resurrection (as if we had to seek forgiveness).
There would still be the problem of sin and death as a result. He, as it says in Hebrews, would have to suffer since the beginning of time (“the foundations of the world”) again and again if His sacrifice was like the blood of bulls and goats (common), but His blood is eternal (hence one sacrifice for all time, for all sin).
To be put simply:
A.) Jesus died to forgive all sin
B.) All sin has been forgiven through the blood of the Lamb
C.) Therefore there is no need for further seeking of forgiveness
D.) Because Jesus through His bloodshed forgave all sin
If we are seeking forgiveness for eternal salvation through sin confession, we have looked past Jesus’ sacrifice which granted for us the remission of our sins. Hence, making His death vain if we seek forgiveness outside of it. One might argue we “apply the blood” through sin confession, but we know that such an application is by faith in Christ. Christ and Him crucified. Not through the act of sin confession as a remedial means of atonement. We place our faith in Jesus Christ, what He did on our behalf (died for our sins and rose on the third day), and we have been forgiven and given eternal life.