And There Were Only Certain Things Priests Could Do For God
The purpose of worship and priestly service is to express the delight of our own hearts and to bring pleasure to God. When the Old Testament priesthood was instituted, the formation of the priesthood and its goal was clearly described.
4 "But the flesh of the bull and its hide and its refuse, you shall burn with fire outside the camp; it is a sin offering.
15 "You shall also take the one ram, and Aaron and his sons shall lay their hands on the head of the ram;
16 and you shall slaughter the ram and shall take its blood and sprinkle it around on the altar.
18 "And you shall offer up in smoke the whole ram on the altar; it is a burnt offering to the LORD: it is a soothing aroma, an offering by fire to the LORD. (Exodus 29:14-18)
They were to offer sacrifices to God as priests so that a sweet smelling aroma will ascend to God. To do this they have to be the proper people, in the proper place, doing the proper thing. The same pattern of priesthood passed over to the New Testament but now all believers are priests. Believe it or not what you do and say can become like a sweet aroma in the presence of God. He has placed you and blessed you to bring pleasure to him. What a wondrous privilege!