But you are not in the flesh, but in the Spirit, if so be that the Spirit of God dwells in you. Now if any man have not the Spirit of Christ, he is none of his.
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Ambrosiaster
AD 400
Those who are said to be in the Spirit are not in the flesh if they agree with the apostle John and do not love the world. … Paul speaks somewhat ambiguously because those who have been inducted into the law do not yet have a perfect faith, although Paul saw a hope of perfection in them. For this reason he sometimes speaks to them as if they are perfect and sometimes as if they are yet to become perfect. This is why sometimes he praises them and sometimes he warns them, so that if they maintain the law of nature according to what has been said above they will be said to be in the Spirit, because the Spirit of God cannot dwell in anyone who follows carnal things. Here Paul says that the Spirit of God is the Spirit of Christ, for everything which belongs to the Father belongs to the Son as well. Therefore he says that whoever is subject to the abovementioned sins does not belong to Christ. Such a person does not have the Spirit of God, even if he has accepted that Christ is God’s Son. For the Holy Spirit abandons people for one of two reasons, either because they think carnally or because they act carnally. Therefore he exhorts them to good behavior by the things which he commands. Commentary on Paul’s Epistles.
