Final answer:
In religious texts, married couples are often described as 'one flesh' to represent their unity and bond.
Step-by-step explanation:
In the context provided, the concept of a married couple being described as 'one flesh' comes from religious texts such as the Bible. This specific phrase appears in the book of Genesis 2:24, where it states 'For this reason a man will leave his father and mother and be united to his wife, and they will become one flesh.' This concept emphasizes the unity and bond between a husband and wife, signifying their physical and emotional union.