How does the offering of firstfruits differ from the grain offering?
Leviticus 2:12 (ESV)
12As an offering of firstfruits you may bring them to the LORD, but they shall not be offered on the altar for a pleasing aroma.
If the offering is of the firstfruits of the land, yeast and honey may be offered with it, but it must not be used as a loyalty offering (see Leviticus 23:17; see also Exodus 23:19; Exodus 34:26; Numbers 15:20; Numbers 18:12).
12 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.