When the Bible refers to “the flesh,” it can mean one of two things. The first meaning of the word flesh pertains to living beings on earth such as animals, birds, and people (1 Corinthians 15:39). But most often the Bible uses the word flesh to refer to the propensity to sin we possess in our earthly existence. Our sinful nature, dominated by sin and rebellion, is so closely tied to the physical aspect of mankind that it is called “the flesh.”