Revelation 4:6-7

Verses 6-7 All of the beauty described above would be reflected in a crystal sea. The four "living creatures," which is a better translation than beasts, are reminiscent of those in Ezekiel 1:1-14; Ezekiel 10:20. Thus, we may assume these are also cherubim. Such were placed on guards over the Garden of Eden and at both ends of the mercy seat. (Genesis 3:24; Exodus 25:18-20) In heaven, they serve the Lord. The faces may represent wild animals or strength (lion), domesticated animals or service (calf or ox), flying creatures or swiftness (eagle), and mankind or intelligence (man). In either case, God is served by all categories of beings.