Romans 7:18
For I know that in me ( that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not. For I know that in me ( that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not.
In this life no good thing dwells in human flesh, so not one person on earth has holy flesh now. Holy flesh is an impossibility that cannot be obtained by faith, and to claim it or to claim perfection in the flesh is error and presumption. Carried further, that claim leads to asserting freedom from sin and holiness of all actions, opening a door of temptation to pollution of body, soul, and spirit.
By contrast, holy hearts may all be obtained now, and Christian perfection of the soul may be had. That present blessing includes perfect forgiveness of sins through the sacrifice and blood of Christ, a conscience freed from condemnation, and favor with God through Christ as Substitute. It includes also sanctification of body, soul, and spirit by surrender to God, faith, obedience to the laws of God, and cooperation with God as laborers together with Him. In that cooperation much can be done to restore His moral image in man and to improve the physical, mental, and moral powers, with great changes made in the physical system by bringing nothing defiling into the body.
Left to themselves human beings are weak and sinful and bent toward evil, unable to do any good thing of themselves. Even with perception of right and desire for goodness, with willing what is right present and with strong resolutions to change, the unaided human will and strength cannot resist and overcome evil or accomplish good. The will may be strong, yet without being directed toward the Lord moral power is weak. Therefore no one can claim goodness or sufficiency in self, rely on own nature, or claim righteousness of own, but must recognize lack of self-sufficiency, depend on Christ alone, and refuse to glorify self. Without God's power human dependence is worthless and leaves the soul defenseless against sin.
As believers advance and come nearer to Christ and see His purity more clearly, they recognize their sinful nature and sin more deeply. Even those whom God has forgiven and accepts as His people experience deepened repentance as Christian experience advances. They humble themselves and confess their need, with sufficiency found in Christ alone. By looking to Jesus they are changed into His likeness, and by cooperation with Him, which is humanity's greatest need, they receive power to resist evil and reach the good ideal they recognize.