Righteousness is that which is right according to God and truth. Righteousness is the content of truth, and the application of the content of truth. Righteousness has nothing to do with human viewpoint, with human attitude, or human arrogance.
Righteousness ultimately produces peace. Peace is the result of righteousness.
Peace is the status of a relaxed mental attitude, which is caused by the intake of Bible doctrine into the soul, as a result of a daily Bible study, learned from instruction.
The effect, or the ministering, or the process of righteousness within the soul is the quietness or stillness of the soul, free from the stresses and anxieties of life.
The effect, is also the assurance, or the place of peace and refuge and assurance and safety and security and confidence.
We typically sum all of these attributes up as spiritual maturity.
And since these are qualities within, and an integral part of, the soul, and the soul having eternal life because of faith in Christ, then that status of spiritual maturity, which includes all of the spiritual resources just listed, and far more, are likewise eternal.
Anything and everything of this world, is temporary at best.
Anything and everything resulting from Bible doctrine learned and inculcated into the soul, is permanent and eternal.
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].