You cannot possibly believe that Paul as Apostle served the law with his mind but that he served the law of sin with his flesh
...that he was still yielding his members as instruments of sin.
I did read your link thanks
You say he struggled as a Christian, I don't believe he did, I believe that sin had no dominion over Paul, I believe he had cast aside the sin which so easily besets in order to run the race.
The struggle is there in the Christian's new life because they have never really understood that we are not under the law but under grace...that is why Christians struggle.
How CAN you struggle with sin that was borne away on the cross 2, 000 years ago? yes it is still in our members that is true, but it is quite dormant, dead.
When the new Christian now starts to apply themselves to come into obedience to the law...any law, even if they make Jesu's commandments law, or other church regulations etc, etc SUDDENLY
SUDDENLY the sin which was dormant, dead, springs back to life...YOU brought it back to life
You are trying to make the flesh which is at enmity with God and which always rears up in rebellion at His law obey. This IS the fierce struggle new Christians have....and old and experienced Christians too.
You are now abandoning the cross in favour of self discipline, soon you will be wearing hairshirts and lying on a bed of nails. You are actually gone back to earning salvation by works.
Stop with the struggle, CEASE, stoppit. confess the sin, get it under the blood of Jesus Christ God's Son....tell the devil to take a hike, remind him that he is defeated and get on with your life.
The revelation will dawn on you...."hey why am I doing this?" the power of sin is the law, if we are not under the law then there is no forbidding.
There is nothing for the flesh to rebel against
We will understand that what we do we do in the light of God's countenance, it becomes an unworthy thing to do and we will get victory...that is to say we will rise up to walk in the victory won for us at the cross...we will walk after the Spirit as in Romans 8.1.