The first five books of the Old Testament are known as the books of the Law. Among other things, they contain the commands of the Law which Moses gave to the people. It wasn’t just Moses, of course. This was God’s law for His people.
The Law addresses everything from routine matters of daily life to specific ordinances for worship. We see an example of this in Leviticus 2:
“When anyone brings a grain offering as an offering to the LORD, his offering shall be of fine flour. He shall pour oil on it and put frankincense on it and bring it to Aaron’s sons the priests. And he shall take from it a handful of the fine flour and oil, with all of its frankincense, and the priest shall burn this as its memorial portion on the altar, a food offering with a pleasing aroma to the LORD. But the rest of the grain offering shall be for Aaron and his sons; it is a most holy part of the LORD’s food offerings. “When you bring a grain offering baked in the oven as an offering, it shall be unleavened loaves of fine flour mixed with oil or unleavened wafers smeared with oil. And if your offering is a grain offering baked on a griddle, it shall be of fine flour unleavened, mixed with oil. You shall break it in pieces and pour oil on it; it is a grain offering. And if your offering is a grain offering cooked in a pan, it shall be made of fine flour with oil. And you shall bring the grain offering that is made of these things to the LORD, and when it is presented to the priest, he shall bring it to the altar. And the priest shall take from the grain offering its memorial portion and burn this on the altar, a food offering with a pleasing aroma to the LORD. But the rest of the grain offering shall be for Aaron and his sons; it is a most holy part of the LORD’s food offerings. “No grain offering that you bring to the LORD shall be made with leaven, for you shall burn no leaven nor any honey as a food offering to the LORD. As an offering of firstfruits you may bring them to the LORD, but they shall not be offered on the altar for a pleasing aroma. You shall season all your grain offerings with salt. You shall not let the salt of the covenant with your God be missing from your grain offering; with all your offerings you shall offer salt.” (Leviticus 2:1–13)
No guesswork is involved here. No reading between the lines. No necessary inferences. No Encyclopedia Brown hermeneutic.
When God wants to specify something, He knows how to specify.