Romans 5:9 says, “…being now justified by his blood, we shall be saved from wrath through him.” This means that believers are under the blood of Christ and no longer under Adamic condemnation.
Although the blood of Christ covers the sins inherited from father Adam, the process of cleansing and spiritual growth is an ongoing work. Even the Apostle Paul struggle against sin.
“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. But I see another law at work in me, waging war against the law of my mind and making me a prisoner of the law of sin at work within me” (Romans 7:18, 23).
The war Paul referred to is the struggle we face each day in overcoming our natural tendencies to sin and be developed in the “fruit of the spirit,” as described in Galatians 5: 22,23. The importance and great benefit of engaging in this warfare is that believers will be prepared to serve as members of the royal priesthood. “But ye are a chosen generation, a royal priesthood, an holy nation, a peculiar people; that ye should shew forth the praises of him who hath called you out of darkness into his marvelous light” (1 Peter 2:9). The work of this priesthood will be to bring mankind back into a relationship with God during the millennium. That will require a spiritually mature class that will then fully possess the mind of Christ (See 1 Corinthians 2:16).
Additional Resource:
(PDF) Herald Magazine Article: “Blood”