What does it mean to be Holy?

Holiness is a condition of the heart that ultimately manifests itself in the outward condition and behavior of the believer. It is living one's life by the spiritual and moral standards of the Lord, not those of this world. The Bible calls us to live by high standards in very clear terms:

Follow peace with all men, and holiness, without which no man shall see the Lord   (Hebrews 12:14)

By the words of Hebrews 12:14, it appears that no man shall see the Lord without holiness. With salvation and the resulting holiness in our life, the result is altogether different:

But now being made free from sin, and become servants to God, ye have your fruit unto holiness, and the end everlasting life. (Romans 6:22)

Remember...

For God hath not called us unto uncleanness, but unto holiness.   (Thessalonians 4:7)

We must serve as an example to the world and be a people set apart by the conduct of our lives. Without holiness no man shall see the Lord.