In the second story of creation, Genesis 2:21 reads: “So the Lord God cast a deep sleep on the man, and while he was asleep, he took out one of his ribs and closed up its place with flesh. The Lord God then built up into a woman the rib that he had taken from the man.” Some important literary imagery needs to be considered.
First, the “deep sleep” denotes God’s divine activity. God Himself is the one creating. In Chapter 2 of Genesis, God created Adam from the earth and breathed life into him, and now He takes from the flesh of the man to create the woman.
Second, why God used a rib is a mystery. However, some scholars suggest that the word “rib” in the ancient Sumerian language means both “rib” and “life.” Accepting this meaning of “life,” all of the phrasing — “rib,” “bone of my bone, flesh of my flesh,” and “man and woman,” — denotes the creative love of God and the original unity of man and woman. Remember in Genesis 1:18, we read, “God created man in His image; in the divine image He created him; male and female He created them.” While each person is made in God’s image and likeness, the complete image and likeness of God is found in marriage when man and woman become one as husband and wife, when the two become one flesh.
Finally, one could find an allegorical or prophetic meaning to this text. Eve, the wife, comes to life from the side of Adam, the husband. Following the teachings of St. Paul and the church fathers, the church, the spouse, comes to life from the side, the heart, of Christ, the Spouse.