‘For those who are after the flesh mind the things of the flesh, but those who are after the Spirit the things of the Spirit.'
The test of whether we walk after the flesh or after the Spirit is revealed by our mind set. Those who walk after the flesh have their minds set on the things of the flesh. Those who walk after the Spirit have their minds set on the things of the Spirit. Compare Colossians 3:1-2, ‘if you then be risen with Christ (Romans 6:1-11), seek those things which are above, where Christ is seated at the right hand of God, set your affections on things above, not on things on the earth --'. If our minds are not set on things above, perhaps we ought to reconsider our position.
Note the use of the third person, continued until Romans 8:9, in order to facilitate the comparison between those who are after the flesh and those who are after the Spirit.