In order to properly answer the question, one should let the Bible define what the word carnal means, rather than his dictionary or lexicon.
After looking at every NT reference for the word 'carnal' I have been able to see that 'carnal' refers to the flesh. Period.
Whomever said there is no such thing as a "carnal christian" should look at this:
1Co 3:1
¶ And I, brethren, could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ.
1Co 3:2
I have fed you with milk, and not with meat: for hitherto ye were not able to bear it, neither yet now are ye able.
1Co 3:3
For ye are yet carnal: for whereas there is among you envying, and strife, and divisions, are ye not carnal, and walk as men?
Clearly Paul says contrariwise to the afore mentioned friend of this board. Obviously, now even as then, there ARE carnal christians.
The context of Romans eight is such that Paul is indeed showing a CONTRAST but it is not that of saved/unsaved. Rather it is maturity in Christ/immaturity in Christ. As such, as he says, one who is immature and living in/for the flesh is at enmity with God. And as Paul says later in the chapter, one who is at enmity with God WILL NOT inherit the glory which will soon be revealed. But and IF one does "suffer with Him" (by putting down the fleshly ways of his body) that christian will be glorified and "reign with Him".
Simple.
Our friend who identified the 'carnal christian' as being the immature babe who does not live, act or speak in a spiritually mature manner; is the correct one in this thread.
Far too many christians in this Laodicean age miss or ignore or redefine things in Scripture which are given to us that we might go on to the full measure in Christ.
Have a nice day.