God is not just like anyone else. His honor is not to be taken lightly; His gifts to the priests were not to be given away to an ordinary person; men’s gifts to Him were not to be anything but the best; His holy days were not to be celebrated casually; and His Name was to be used with respect, never to be cursed.
Among the things that you are likely to notice in the book of Leviticus is this emphasis on holiness. In the 21st century western world, where casualness and egalitarianism is the rule and the norm, we are likely to think that Leviticus is indulging in a little exuberant hyperbole — until we see those who treat God too familiarly, too lightly, receive the death penalty. He was quite serious about it, and since God’s nature doesn’t change, we would do well for our soul’s sake to also treat Him as the holy being that He is. He is not like men, even like a king or other political dignitary — He is greater, nobler, higher, and worthier. He is not like the other so-called “gods” of the world who are supposedly due great honor and respect and get it from their worshippers — He is higher, greater, more powerful, and due the greatest of honor and respect, because He is real!
So, when the Lord tells us that gifts He has given to His priests ought not be squandered on the vulgar or common, we can reap the principle that the gifts He gives us should be stewarded well. When we read how God should not be given anything that is blemished or lacking, we need to reap the principle that He is deserving of our best efforts, our best time, our best products, our first fruits — our best, period. When we read of the holy days that He commanded Israel to observe with their correlated Sabbath observances, we should harvest the principle that we need to give God full attention in worship times. When we read of how severely an angry usage of His name received the sternest of consequences, we need to take warning regarding our own words.
We’d like to make God our buddy, but He is not. He has condescended to allow us to call Him Father, to call us His sons, to allow us to approach His throne through Jesus His only begotten Son, to invite us to unburden ourselves on Him in prayer, because He cares for us — but He is still holy.