NOTES for Rom 12:1-2
In speaking of the Christian life and ministries in the Church, Paul singles out the chief thing that unites them all: the spiritual renewal of the human person. The person himself must become a sacrifice to God, and this is possible only through the “renewal of the mind.” No other ministry can be considered reasonable from a Christian point of view.
Indeed, Christianity is not a religion, but life with Christ in His Kingdom. Everything else, including every form of ministry, is merely a way and a form of such life. And the Church is not a religious organization, but the Body of Christ, as the apostle calls it, the spiritual space of the relationships that unite the faithful with Christ. The Church's chief task is precisely this: to remain such a space, the Body of Christ.
And any ministry by any member of the Church, if we are speaking of genuine ministry, is possible only in the context of that person's relationship with Christ and as a form in which such a relationship exists. One might say that every ministry in the Church is, on the one hand, a way for a Christian to exist as part of the Body of Christ and, on the other, a form in which that Body is manifested in the Christian's life. That is why the “renewal of the mind” remains the chief task in every ministry.
In his epistles Paul often uses the word mind for what other biblical books call the heart: the spiritual “self” of the human person, the core and foundation of one's personality. It is there that who and what a person will be before God and other people is determined, for there lies the source of the human will and therefore of all one's intentions, which determine the content of one's spiritual life. The inner Torah is rooted precisely there, in the mind as Paul understands it. And only from there can the transformation of a person into a living sacrifice begin, so that one's ministry may become reasonable from a Christian point of view.
Indeed, sacrifice in Yahwism was the principal form of communion with God. The sacrifice was sanctified on the altar by God's presence abiding there, and then in turn sanctified everyone who ate it by taking part in the sacrificial meal. Christians too are called to sanctification so that they may carry the Kingdom into the world and sanctify it by their presence. To remain sanctified and not lose this state is the Christian's chief task, and it can be preserved only through awareness of one's own life, which is impossible without the renewal of the mind of which the apostle speaks.
The Christian's chief task is to learn to exist in the Kingdom, in God's presence which sanctifies the world, and to become an instrument of that sanctification. Everything else, all ministries in the Church, consists merely of forms and ways of such existence. Provided, of course, that they are reasonable.