In Scripture, the concept of holiness is complex. But it’s fair to say that when the Bible refers to someone or something as holy, the most basic idea is that the subject is “morally pure.”

When we say that someone or something is morally pure, we mean that it’s free from sin and corruption. Because God is utterly holy, anything sinful that enters his immediate presence is subject to his judgment and wrath. Although God may withhold judgment for a while, his holy presence will ultimately destroy those whose sin is not covered. As a result, anyone or anything that is to enter his presence must first be made holy. For instance, consider Isaiah’s words in Isaiah 6:3-7:

[The seraphim] were calling to one another: "Holy, holy, holy is the Lord Almighty” ... "Woe to me!" I cried. "I am ruined! For I am a man of unclean lips, and I live among a people of unclean lips, and my eyes have seen the King, the Lord Almighty." Then one of the seraphs flew to me with a live coal in his hand, which he had taken with tongs from the altar. With it he touched my mouth and said ... "[Y]our guilt is taken away and your sin atoned for."

By this cleansing, Isaiah was purified from sin — he was made holy. And because of his new holiness, he was able to stand in the Lord’s presence without falling under judgment.

We are to strive to be as morally pure as God is. Of course, in our own strength, we can never succeed in this attempt. But Christ himself has perfect moral purity. And when we are in him, his righteousness is credited to us, and we are counted as being absolutely pure, completely free from sin and corruption.

And in a related sense, “holy” can also describe people and things that are set apart for use in special service to God. In this sense, things can be holy even if they are not morally pure. As just one example, listen to what Paul wrote in 1 Corinthians 7:14:

The unbelieving husband is made holy through his wife, and the unbelieving wife is made holy through her husband. (NRSV)

Here, Paul said that when a believer is married to an unbeliever, the unbeliever is made holy, or as other translations put it, the unbeliever is “sanctified.” The idea is that the unbeliever is identified with God and made useful for his service — even though the unbeliever has not been morally purified by God in Christ.

Not everyone in Israel or the New Testament church was a true believer. Even so, they were all considered holy because they were part of God’s covenant community, that is, the people who were in covenant with God.

For the believers in the covenant community, their holiness exceeded the holiness of the unbelievers. Unbelievers were holy only because they were set apart for God. But believers were holy not only because they were set apart, but also because, in Christ, they were morally pure and obedient to God. Of course, the goal was always for the entire covenant community to believe — for everyone to be faithful to God and to live morally pure lives.

Whatever the case, one thing we know is that everything and everyone that is holy is special to God. We revere God’s name, refusing to take it in vain, because it’s holy. We submit to the Bible because it’s the holy word of our holy God. We respect and strive for moral purity in every aspect of life, knowing that the Lord calls us to holy lives. And we participate in and submit to his holy church. Wherever we find holiness, we recognize God’s hand, and we take special care to treat it with godly respect.