Holiness of God
At least four heavenly angelic creatures hover around the throne of God and chant to Him unceasingly, “Holy, holy, holy,” and then either, “is the LORD of hosts: the whole earth is full of his glory” (Isaiah 6:3) or “Lord God Almighty, which was, and is, and is to come” (Revelation 4:8).
Many, and probably truly, call holiness the primary attribute of God. One would think it is because of what those angels continuously exclaim to the Lord. Also, holiness characterizes all the other attributes. Every other attribute of God is holy.
Holiness refers to the separateness of God, so nothing can profane any of those perfections of His attributes. They remain pristine, which is His majesty. God never acts in an unholy manner. Neither does anything stain, besmirch, alter, or render common any of His nature. He does not allow the sinful in His special presence, that is, in proximity to Him.
To reverence God would mean to reflect that nature of holiness, not to associate anything with God that would in any way desecrate Him. This is glorifying God. Romans 12:1 says that the life of the believer is presenting or offering one’s self holy and acceptable unto God. This task takes precedent over pleasing self, enjoying self, having fun, and being entertained. A true believer would want rather joy as a byproduct of giving God what He wants.
A synonym of “holy” is “sacred.” Historically, churches wanted to keep their gatherings for the Lord to be sacred. It is why they would call where they met and meet, a sanctuary, which is a sacred place, set apart from the plain ordinary world.