As obedient children, do not conform to the evil desires you had when you lived in ignorance. But just as he who called you is holy, so be holy in all you do; for it is written, “Be holy, as I am holy.” 1 Peter 1:14–16 NIV
May God himself, the God of wholeness, make you completely holy. May your whole spirit, soul, and body be completely whole until the coming of our Lord Jesus Christ. He who calls you is faithful, and he will do it. 1 Thessalonians 5:23–25 Author’s translation
There are three thoughts that capture my attention when I look at the three verses from 1 Peter. Let’s look at them in reverse order. First, “it is written.” Written where? Well, Peter is quoting from the Old Testament book of Leviticus where the command appears in these words four different times (11:44–45; 19:2; 20:7, 26). Yahweh is speaking in the context of the Covenant; if you are going to be in a covenant with a great king, you do what he says. But this is more than merely doing what he says; it is being what he is and doing what he does. Pretty shocking.
The second thing I notice here is the statement “be holy in all you do.” Some contemporary Christian teachers tell us that holiness is not a particular kind of behavior, but merely a condition: you belong to God and are set apart for his use, like a vessel in the temple. But that is not what Peter says, is it? He says holiness is a way of acting. That corresponds perfectly with Leviticus 19. The chapter begins with the command for us to be holy, and the rest of the chapter, beginning with a command to honor our parents, is a whole series of commands to do or not do certain things. Interestingly, the topics are all mixed together, without any clear organization, and they cover the whole gamut of life. Be holy in all you do.
But what is it about these commands that is particularly holy? Here is where Peter’s third thing, and the first in his order, comes into play. Why does God have to command us to be holy; why is it not something we do ordinarily? “Evil desires.” But what are those? The issue becomes clear when we look at the commands of Leviticus 19. What do they all have in common? They are all other-oriented! To be holy is to be focused on the good of others, just as our God is supremely focused. But our “evil desires” and the desires of the world in which we live are focused squarely in the opposite direction – on ourselves. We are focused inward, not outward. So God wants to change our orientation. What a thought! But this is not something we can do for ourselves. It has to happen through the power of Spirit of Christ living in us. What we do have to do, and this is where the command comes in, is to give him permission to do this (not necessarily an easy decision to make), and we do have to believe him to do it. But if we do our part, then, as Paul says, he is absolutely faithful to do his part.