We prioritize every day with even the most mundane activities. Putting the dishes in the dishwasher before turning the dishwasher on is one example of a mundane task that can work only if your priorities are correct. The principle holds when dealing with much more important matters as well. Up to this point, Peter has instructed, exhorted and admonished us to walk in a manner which is worthy of the calling we have in Christ. But lest we fail to prioritize correctly, he tells us what to place at the top of the list. In verse 6, Peter tells us that for all of God's people in this time before the end of all things, whether alive or dead, whether suffering the judgment of sinners or taken from this world to their heavenly home, His purposes are being fulfilled in them. As a result, they ought not be discouraged or distracted. Nor should we succumb to the temptation to compromise in doctrine or life. Rather, we ought to "…earnestly contend for the faith which was once delivered unto the saints." (Jude 3)
In verse 7, Peter shifts focus from the time before the end of all things toward the end. As Peter has focused our attention on the pilgrim in this world, he has not forgotten to remind you that things will not always be as they are; the pilgrim life is just that, a pilgrimage. This means that the end is always in our view. Whether the end of life, the end of sinning or the end of everything, an end is always in view. Therefore, the Christian's priorities are, and ought to be, different than the world's priorities. The Christian's priorities reflect the fact of the conflict with sin in this world, and also reflect the spiritual nature of the conflict in this world. (II Cor. 10:3-5) To this end, Peter exhorts us to a sober (not somber) manner of life and thought. The sober-minded Christian sees the world correctly because the world is perceived through the lenses of God's revelation, and the sober-minded Christian, rather than lashing out, prays in the confidence that God is sovereign. So don't panic; don't neglect the needful things, but organize your life and priorities around the absolute and unshakable truth that, while the end is in sight, for the follower of Christ it is not meaningless and purposeless, but the execution of the eternal plan.
Lastly, in verse 8, the inspired apostle lays before you the most important thing: to have fervent charity. Throughout his letter, Peter has labored greatly to lay before you a system of doctrine which shows the glories of your life in Christ, but here as he begins to sum it all up, his concern is not to make a minor or inaccessible doctrinal point. His concern reveals a true weakness; a weakness revealed in the church at Ephesus in Rev. 2:2-4 That is, the purity of the doctrine of that church was not matched by a zealous love and they had forgotten first principles. As fervently as we seek to be true to the doctrine of Scripture we must not neglect to fervently seek and practice the ethics of Scripture. The charity (undeserved love) which we have experienced in the Savior, ought to be shown to others. The Savior shed His blood as an atonement for the sins of His people, and thus, provided a covering for us to cover our nakedness. It was the supreme act of charity. Likewise, in following Christ who shed His blood for us, we are to "cover" the offenses made against us. Not that we excuse sin, but as the Savior taught us, "forgive us our debts as we forgive our debtors." That is, follow in the footsteps of the Savior. We know that offences will come and we all need the forgiveness, that is, the charity, of others.