There are two meanings to the word "Holy"; one is our personal righteousness and purity, the other is that we are separate. That which is Holy is that which is "other", that which is different from something else. We say Holy is defined as "the otherness of God". When the Bible speaks of God's Holiness, the primary thrust is to refer to God's transcendence, His magnificence, to that sense in which God is higher and superior to anything that there is in the creaturely realm. That which is Holy is that which is different. When God says, "Be Holy for I am holy," He is saying be different than the normal standards of this world. That is the task of the Christian - to mirror and to reflect the character of God to a dying world.
The Holiness of God's judgment will be a consuming fire. It will be a spiritual death the likes of which are so drastic, that necessitated a crucifixion of the Holy One of God. Christ tasted death so that you would not have to.
Do you call upon the Holy One, Christ, on Him as Savior, trusting His sacrifice, His death, His resurrection? And do you call upon the Holy God, that you might be ransomed for sin and from sin? Death and life are before you. Choose life, calling upon Christ and be saved, for in your treason against God who is Holy, when humbled by this Holy God, He will save you by His grace.