Paul describes two warring factions that exist within each person. The law within the members, refers to the law of sin that resides within the physical body of the individual.
The law of the mind, refers to the individual’s ability to decide. We typically call this a person’s volition.
When there is no other mechanism to combat sin, then the sin nature that resides within the physical body, will drive the individuals decisions toward sin.
When there is a mechanism available to combat sin, namely Bible doctrine, which when learned is resident within the soul of the individual, then the individual has the ability to choose against sin, based on discernment and understanding that comes to the individual as a result of learning Bible doctrine.
However, Bible doctrine, is only available to believers only. Believers are those individuals who have believed in Christ.
While we all reside in our physical bodies, we are in a trap, or a prison, being held captive to the sin nature. And we cannot escape that captivity until and unless we believe in Christ, and therefore have salvation, which gives us temporary release while still in this life. And then eventually permanent release when we leave this world, leaving our physical body behind.
The only means of correction or perfection that a person can attain, is by means of faith in Christ, and then eventually leaving this world, and leaving the corruption of the physical body, namely the sin nature, behind.
There is no method or means of gaining perfection while in this world.
We cannot make ourselves perfect.
We cannot make this world perfect.
Sin and the sin nature, are the principal ingredients of the disintegration and destruction of this world and of life in general.
Study [by instruction],
to show thyself approved [spiritually mature]
a workman [student]
that need not be ashamed [ignorant],
rightly dividing [learning, understanding, discerning]
the word of truth [Bible doctrine].
If you can dream and not make dreams your master,
If you can think and not let thoughts narrow your views,
If you can meet triumph with disaster equally,
If you can learn and see your full meaning and purpose in life,
Then you can believe in Christ, learn Bible doctrine, and grow far beyond the potential that God has prepared for you.