“Behold, God puts no trust in his holy ones, and the heavens are not pure in his sight;” Job 15:15 (ESV)
Often when I think of the word holy I think of sin, that is the lack of sin. To me the main concept of holiness is sinlessness. Maybe this is because often when we talk about what it means to be holy we speak about being without sin. However there is so much more to the meaning of holy than this, especially when talking about God. As you may know the word holy does not mean without sin (although when speaking of God it does imply this of course), the word holy means separated. God is completely separated from every other thing in the universe.
This extreme separation can be seen in this verse, this is what I believe we should see in it. This is because the verse is not trying to tell us that the heavens and the beings that dwell there are corrupted and sinful, but that they are not holy as God is holy. This should be amazing to us as humans. The holiness and perfection of heaven and the angels are not even holy compared to God himself. This can also be seen in Isaiah 6:2-3. The Seraphim, sinless powerful creatures that would be terrifying to any of us cry out “holy, holy, holy” in God’s presence.
God alone is truly holy, it is his nature to be so. Also God alone is the only being that is holy in himself. The holiness of the heavens and angels flows only from God himself. The same with us as followers of Christ, our holiness alone comes from God’s grace.