"Holy" is the word that sets God apart and above our attempts to enlist him in our wish-fulfillment fantasies or our utopian schemes for making our mark in the world. Holy means that God is alive on God's terms, alive in a way that exceeds our experience and imagination. Holy refers to life burning with an intense purity that transforms everything it touches into itself.
Because the core of all living is God, and God is a holy god, we require much teaching and long training for living in response to God as he is and not as we want him to be. All our god-fantasies of "give us what we want when we want it on our own terms" in fact do is cripple or kill us. Leviticus is a start at the much teaching and long training that continues to be adapted and reworked in every country and culture where God is forming a saved people to live as he created them to live - hold as God is holy.
The first thing that strikes us as we read Leviticus in this light is that this holy God is actually present with us and virtually every detail of our lives is affected by the presence of this holy God; nothing in us, our relationships, or environment is left out. The second thing is that God provides a way (the sacrifices and feasts and Sabbaths) to bring everything in and about us into his holy presence, transformed in the fiery blaze of the holy. It is an awesome thing to come into his presence and we, like ancient Israel, stand in his presence at every moment. Our Lord is not dwelling in a tent or house in our neighborhood. But he makes his habitation in us and among us as believers and says, "I am holy; you be holy." (Leviticus 11:44)
Once we realize this, the seemingly endless details and instructions of Leviticus become signposts of good news to us: God cares that much about the details of or lives, willing everything in and about us into the transformation that St. Paul later commended:
"So here's what I want you to do, God helping you: Take your everyday, ordinary life - your sleeping, eating, going-to-work, and walking-around life - and place it before God as an offering. Embracing what God does for you is the best thing you can do for him. Don't become so well-adjusted to your culture that you fit into it without even thinking. Instead, fix your attention on God. You'll be changed from the inside out. Readily recognize what he wants from you, and quickly respond to it. Unlike the culture around you, always dragging you down to its level of immaturity, God brings the best out of you, develops well-formed maturity in you." (Romans 12:1-2)
PS, sorry its so long!