Worship the LORD in the beauty of holiness.
Ps. 29:2
Leviticus chapter 10 relates the account of Nadab and Abibhu's failure to render to the LORD the proper respect in regard to their ministry in the tabernacle. It seems they were intoxicated with alcohol (v.9) and as a result they offered up profane fire to the LORD which He had not commanded them. The LORD was angry and fire went out from Him and devoured them and they died.
The word of the LORD in this situation was:
By those who come near Me I must be regarded as holy;
And before all the people I must be glorifed.
Lev. 10:3
There is something very vital and important for us to learn from this tale and that is that God is not to be trifled with. As the writer of Hebrews reminds us, "Our God is a consuming fire" and we should serve Him with "reverance and godly fear" (Heb. 12:28,29). We ought to be very mindful of God's holiness and our own unworthiness to stand before a holy God and we ought to understand that we can only come near Him on his terms and because of His grace and mercy. For the Israelites of the Old Testament that meant observing all the rules and regulations the LORD gave them concerning worship around the tabernacle and as they learnt through the example of Nadab and Abihu, the consequence of disobeying those laws was catastrophic.
For us today the way into God's presence is by that "new and living way" which the Lord Jesus consecrated for us by His blood, it is a way that was bought for us at great price, and it gives us boldness and confidence in the very presence of God (Heb. 10:19-22). Does that mean we no longer need to show respect, awe and reverance in God's presence? Not at all, God remains absolutely holy, we remain unworthy sinners who are not fit to be in His presence, it is still only by His grace in providing atonement for us that we can draw near to Him. We should be ever mindful of the price He paid, and of the wondrous privilege we have in being granted access to Him. This is not something to take lightly, He still requires that we regard Him as holy.

What is holiness?
We need to understand the true Biblical meaning of holiness, it is far from the world's idea.
The Old Testament word is KADOSH
The New Testament word is HAGNOS
The meaning of both is very similar - separation and ethical purity.
To be holy means to be separate and to live a righteous life.
The Bible makes it very clear that only God can be regarded as absolutely holy:
Ex. 15:11 - "Who is like you, O LORD, among the gods? Who is like you, glorious in holiness?
1Sam. 2:2 - "No one is holy like the LORD."
God is holy because he is separate from all sin and evil, He is the "Holy One" who is of "purer eyes than to behold evil" (Hab.1:12,14).
He alone is righteous in all His ways.

There is no one in this world who is holy and righteous like God. Because man is unholy He has no way to enter God's presence, no merit of his own, in God's eyes he is evil and God cannot look upon him. God will not and cannot ever compromise His holiness, he can not overlook sin, he cannot say, "Oh its only a little sin, never mind." Those who enter His presence must appear before Him without sin.
So, God provides the atonement, in the Old Testament He gave them the sacrifices and the rituals, He gave them the Day of Atonement, the people did not invent these things. The LORD told them what they must do in order to find acceptance with Him.
Then He sent His Son, Jesus to be the atonement for the sins of the world so that we might have the full forgiveness of sin through the merit of the shed blood of Jesus. God again provided for our atonement and the means of access to His presence. No human being thought these things up, God did it out of His great love and mercy for us poor lost sinners.
Only God is holy and only God can make us holy.

Holiness is separation
People and objects could be called holy:
Ex. 3:5 - The LORD said to Moses, "The place where you stand is holy ground." What made it holy? It was just a patch of sand at the back of the desert, nothing extraodinary about it at all. It was holy because it was chosen by the LORD for a specific purpose, He appeared there, He spoke to Moses there, He chose and separated that piece of ground for His own purpose, that's what made it holy. If you could go to the same spot today it would be just ordinary.
Ex. 19:3-6 - The LORD chose the people of Israel and called them a Holy Nation. Why? There was nothing special about them, nothing extraordinary to set them apart from other nations. They were holy because they were chosen by the LORD for His own purposes and He made them separate from the other nations. He gave them His laws to keep them separate.

There was a process to holiness:
In Ex.29 and Lev. 8 you can read how the priests were consecrated for their work in the tabernacle. They had to be washed in water, they had to be anointed with oil, they had to make sacrifices and the blood of the animals was put on their ears, thumbs and toes. This was all done to "hallow" them for the holy work of the priesthood.

The people could dedicate themselves, their animals and possessions to be "holy to the LORD" (Lev.27)

And the people were told how to conduct themselves as a holy nation. In Lev. 19:2 they were told, "You shall be holy, for I the LORD your God am holy." There follows a long list of do's and don't's, the LORD chose them, He made them His own Holy people and He set the standard for their conduct. They were to be separate from all other nations - in the way they worshipped and in the way they conducted themselves.

It is very important to remember the two scriptural principles that make holiness - separation and right conduct. The separating is done by God and for His own purposes and He sets the standards for conduct. None of this can be accomplished by human effort.

New Testament Saints
The principles for holiness remain the same in the New Testament:

1. God chooses:
2Tim. 1:8,9 - "... God, who has saved us with a holy calling, not according to our works, but according to His own purpose and grace which was given to us in Christ Jesus before time began."

2. There must be cleansing:
Titus 3:4,5 - "But when the kindness and the love of God our Saviour toward man appeared, not by works of righteousness which we have done, but according to His mercy He saved us, through the washing of regeneration and renewing of the Holy Spirit, whom He poured out on us abundantly through Jesus Christ our Saviour."

3. There is an anointing:
Eph. 1:13 - "In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also having believed, you were sealed with the Holy Spirit of promise."
Every born again believer receives the seal of the Holy Spirit, it is like a mark upon their spirit that they belong to God. Oil in the Old Testament is often symbolic of the Holy Spirit.

4. There is the dedication of our lives:
Rom. 6:13 - "Therefore do not present your members as instruments of unrighteousness to sin, but present yourselves to God as being alive from the dead, and your members as instruments of righteousness to God."

5. There is the call to righteous conduct:
1Pet. 1:15,16 - "But as He who called you is holy, you also be holy in all your conduct, because it is written, "Be holy, for I am holy.""
Read Eph. 4:17 - 5:33 to see how a holy person should conduct themselves in this world.

Who then is a holy person?
One chosen by God, washed in the blood of Jesus, sealed by the Holy Spirit, who has offered up their life in service to God and conducts themselves according to the word of God.
Such people are the saints, the holy ones of God.

What does all this mean for our church?
We are told to worship the Lord in the beauty of holiness.
What is that beauty? It is the absence of sin or anything that would defile the holiness of God. If we are to worship Him in that beauty we must be cleansed from our sin. You cannot worship Him if you have unconfessed sin in your life, you can go through all the actions of worship, singing, raising your hands etc., etc., but the Lord will not accept your worship, He is of purer eyes than to behold evil. Confess your sin, the blood of Christ will cleanse you and you will be fit to enter God's presence and He will accept you.
He must be regarded as holy. I find this is lacking in far too many churches today, somehow we have come to treat a holy God as if He is the "guy next door", a matey sort of pal who wouldn't say boo to a goose, a God who is not too concerned about our "little misdemeanours", a God who doesn't need us to be serious about worship. This sort of attitude does a great injustice to the holiness of God - He has not changed His standards nor has he changed his mind about sin. He punished Nadab and Abihu with death because they failed to approach him without the right regard to His holiness, will he do the same today? Yes, He will certainly chastise when holiness and the right regard to it is lacking, read Heb. 12, and look closely at verse 10. He does chastise us, and He does it in order that we might "be partakers of His holiness." Our Heavenly Father desires His children to be like Him in holiness, children take on the characteristics of their parents, those who are born again children of God should be like him, and He will chastise when we sin and fall short.
The beauty of holiness is found in separation, it is separation from sin and from the ways of this wicked world. Those who truly worship Him in the beauty of holiness have been chosen by Him, they have been called and taken out of the world by Him, and because of this they love Him, they are thankful to Him and they are prepared to dedicate their lives to serving Him. Too often we think worship is just about lifting up our hands, I hope that this article may go some way to helping us see there is much more to it than that.

Psalm 93:5 says, "Holiness adorns your house, O LORD, forever." Can we say that the beauty of holiness is the adornment of our church meetings. If we come before our God with awe, with reverence, with respect, with thankfulness; if we come before Him with clean hands and pure hearts knowing we have confessed our sins, if we come without the taint of the world and its thoughts and ideas, if we regard our God as holy and treat Him as such then we will be ready to worship Him and He will meet with us, draw us deep into His very presence and not just the church but our very lives will carry that beautiful adornment of the holiness of God wherever we go.