Carnal is a biblical term, used to refer to “the flesh”. A carnal person, or a person who is acting carnally, is acting “fleshy”.
Although this term is often used to compare a “civilized” or “refined” person with a base, lusty or gross person the actual biblical use of the term is quite different. In the New Testament the term flesh is a synonym for normal human behavior and is contrasted with spiritual, which refers to the characteristics of a person who is acting in accordance with the Spirit of God.
For example, in I Corinthians 3:1 Paul says that he could not give them advanced teaching because they were still carnal. Reading this in context we see that he is referring to envy, competition and strife between members of that church. That is, they were just acting like ordinary people. They had not yet learned to resist their lower nature and walk as “new creatures”. To be spiritual (and not carnal) would require that those people would detach from their ambition and desire the best for the church as a whole and work together to advance God’s kingdom.
The most complete description of biblical carnality in given in Galatians chapter 5, where Paul is contrasting the flesh with the spirit: “Now the works of the flesh are clear enough: adultery, fornication, uncleanness, lasciviousness, idolatry, witchcraft, hatred, variance, emulations, strife, seditions, heresies, envying, murders, drunkenness, revelings and the other similar things”. Notice that while some items in this list are “base, lusty and gross” others of them, like envy, variance (divergent), emulations (competitive imitation), strife and sedition (inciting discontent) are found in the most refined and genteel of women and in most elder meetings.
Therefore, to stop being carnal means to stop being a normal human being. That is why Paul also says, talking to Christians, that we are not “children of wrath, like the rest of mankind”. In short, a “new person in Christ” should think and act differently than someone who has not been converted. This is especially true when we realize that purification applies to internal states as well as to behavior.