The term "cherub" comes up in the Bible almost from the outset, with the story of the expulsion from the Garden of Eden. After Yahweh creates the universe by organizing it from primordial chaos, He plants a Garden called Eden. This garden is a paradise of blurry innocence. There is no aggression, no death, and no sexuality. There are no hard edges to identity, and indeed Adam and Eve are originally created together as a sort of hermaphroditic man-woman creature (cf. Aristophanes' delightful riff in Plato's Symposium), before Yahweh separates them into a two distinct individuals. Adam and Eve live in an infantile state, like blissful babies who are not aware of any selfhood or otherness, having no needs beyond the giant, engulfing warmth of the mother’s breast.
In addition to the many pleasant trees and plants in the garden of Eden, there are two trees which possess supernatural powers—the Tree of Knowledge and the Tree of Life. Adam and Eve are forbidden to eat from the Tree of Knowledge, “for in the day that thou eatest thereof thou shalt surely die.” In partaking of it’s fruit and opening their eyes to knowledge, Adam and Eve lose their innocence and transform their idyllic world into a harsh kingdom ruled by the bloody tyranny of nature. When they are cast out of Eden and into this bleak world, and Yahweh reasons thusly: “Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever:” and elects to place at the east of the garden of Eden “Cherubims, and a flaming sword which turned every way to keep the way of the tree of life.” The “Cherubims” turn every way, presumably in the four cardinal directions, as did the four rivers which sprang from the center of Eden. The design of this creature, or creatures, is to block Adam and Eve from sneaking back into Eden, eat from the Tree of Life, and become immortal in their sinful state. Boundaries are created around the once free and open garden, and mankind is blocked access to his original innocence and to eternal life. The only thing standing between mankind and immortality is the terrifying Cherub, who faces us no matter which way we turn.
Cherubim are frequently mentioned in relation to the ornamentation of the temple, particularly with the Ark of the Covenant, the holy repository of the Tablets of the Law. In Chronicles, the inspired David instructs his son and successor, Solomon, to fashion “the pattern of the chariot of the cherubims, that spread out their wings, and covered the ark of the covenant of the LORD.” Two cherubim were to be fashioned of gold to adorn each side of the “mercy seat,” which sat atop the ark. The word used in the text to designate this piece of divine furniture is kaporet, or “atonement piece.” The word probably descends from kaphar, meaning “to cover.” The Ark, complete with kaporet, resided in the center of the Temple, the holy of holies, which Yahweh had filled with a divine cloud of light as He entered in to accept its dedication. This kaporet, then essentially constituted the throne Yahweh’s divine chariot, with the cherubim acting as exalted steed to draw it forward. It is upon such a throne, in visionary form, that we must suppose Ezekiel beholds Yahweh above the Chebar. The Cherubim, then, may be considered a synecdoche for the Chariot/Throne of the Presence of Yahweh.