For the mind set on the flesh is death, but the mind set on the Spirit is life and peace. (Rom 8:6)

“Wherefore, the “minding of the Spirit” is the actual exercise of the mind as renewed by the Holy Ghost, as furnished with a principle of spiritual life and light, in its conception of spiritual things and the setting of its affections [inclinations] on them, as finding that relish and savour in them wherewith it is pleased and satisfied. … “To be spiritually minded;” that is, to have the mind changed and renewed by a principle of spiritual life and light, so as to be continually acted and influenced thereby unto thoughts and meditations of spiritual things, from the affections cleaving unto them with delight and satisfaction. …

It will therefore be no small advantage unto us to have our souls and consciences always affected with and in due subjection unto the power of this truth,—namely, that “to be spiritually minded is life and peace;” whence it will follow, that whatever we may think otherwise, if we are not so, we have neither of them, neither life nor peace. It will, I say, be of use unto us if we are affected with the power of it; for many greatly deceive themselves in hearing the word. They admit of sacred truths in their understanding, and assent unto them, but take not in the power of them on their consciences, nor strictly judge of their state and condition by them, which proves their ruin; for hereby they seem to themselves to believe that whereof in truth they believe not one syllable as they ought. They hear it, they understand it in the notion of it, they assent unto it, at least they do not contradict it, yea, they commend it oftentimes and approve of it, but yet they believe it not; for if they did, they would judge themselves by it, and reckon on it that it will be with them at the last day according as things are determined therein. …

When there is in any a love of earthly things that is predominant, whence a person may be rightly denominated to be earthly minded, he is not, nor can be, spiritually minded at all; he hath no interest in the frame of heart and spirit intended thereby. And thus it is evidently with the greatest part of them who are called Christians in the world, let them pretend what they will to the contrary.” (John Owen, Of Spiritual Mindedness, vol. 7, 270-273)