Question: "What are cherubim? Are cherubs angels?"
Answer: Cherubim / cherubs are angelic beings involved in the worship and praise of God. The cherubim are first mentioned in the Bible in Genesis 3:24, "After He drove the man out, He placed on the east side of the Garden of Eden cherubim and a flaming sword flashing back and forth to guard the way to the tree of life." Prior to his rebellion, Satan was a cherub (Ezekiel 28:12-15). The tabernacle and temple along with their articles contained many representations of cherubim (Exodus 25:17-22; 26:1,31; 36:8; 1 Kings 6:23-35; 7:29-36; 8:6-7; 1 Chronicles 28:18; 2 Chronicles 3:7-14; 5:7-8; Hebrews 9:5).
Chapters 1 and 10 of the book of Ezekiel describe the "four living creatures" (Ezekiel 1:5) as the same beings as the cherubim (Ezekiel 10). Each had four faces - that of a man, a lion, an ox, and an eagle (Ezekiel 1:10; also 10:14) - and each had four wings. In their appearance, the cherubim "had the likeness of a man" (Ezekiel 1:5). These cherubim used two of their wings for flying and the other two for covering their bodies (Ezekiel 1:6,11,23). Under their wings the cherubim appeared to have the form, or likeness, of a man's hand (Ezekiel 1:8; 10:7-8,21).
The imagery of Revelation 4:6-9 also seems to be describing cherubs. The cherubs served the purpose of magnifying the holiness and power of God. This is one of their main responsibilities throughout the Bible. In addition to singing God's praises, they also served as a visible reminder of the majesty and glory of God and His abiding presence with His people.