These four creatures symbolize different types of beings:
a lion represents wild animals,
an ox represents domesticated animals,
a human represents humanity, and
an eagle represents birds (see Ezekiel 1:10).
These figures come from Ezekiel 1 (cherubim) and Isaiah 6 (seraphim). They likely represent the best of creation as worshiping God. Missing from this group of created beings are fish. Ancient people often connected fish with the dangerous or evil sea (see Revelation 21:1). Insects are also missing. In Revelation, insects are linked to locusts that belong to the evil kingdom (see Revelation 9:1–11).