Thus a true sacrifice is every work which is done so that we may be united to God in holy fellowship, and which is directed to that supreme good and end in which alone we can be truly blessed. And therefore even the mercy we show to men, if it is not shown for God's sake, is not a sacrifice. For, though made or offered by man, sacrifice is a divine thing, as those who called it sacrifice meant to indicate. Thus man himself, consecrated in the name of God, and vowed to God, is a sacrifice insofar as he dies to the world so that he may live to God. For this is a part of that mercy which each man shows to himself; as it is written, “Have mercy on your soul by pleasing God.”⁠a Our body, too, is a sacrifice when we discipline it by temperance, if we do so as we ought, for God's sake, so that we may not yield our members as instruments of unrighteousness to sin, but instruments of righteousness to God. Romans 6:13 Exhorting to this sacrifice, the apostle says, “I beg you, therefore, brothers, by the mercy of God, to present your bodies as a living sacrifice, holy, acceptable to God, which is your reasonable service.” Romans 12:1 If, then, the body, which, being inferior, the soul uses as a servant or instrument, is a sacrifice when it is used rightly, and with reference to God, how much more does the soul itself become a sacrifice when it offers itself to God, so that, inflamed by the fire of His love, it may receive of His beauty and become pleasing to Him, losing the shape of earthly desire, and being remolded in the image of permanent loveliness? And this, indeed, the apostle adds, saying, “And do not be conformed to this world; but be transformed in the renewing of your mind, so that you may discern what is that good, and acceptable, and perfect will of God.” Romans 12:2 Since, therefore, true sacrifices are works of mercy to ourselves or others, done with reference to God, and since works of mercy have no other object than the relief of distress or the conferring of happiness, and since there is no happiness apart from that good of which it is said, “It is good for me to be very near to God,” it follows that the whole redeemed city, that is to say, the congregation or community of the saints, is offered to God as our sacrifice through the great High Priest, who offered Himself to God in His passion for us, so that we might be members of this glorious head, according to the form of a servant. For it was this form He offered, in this He was offered, because it is according to it He is Mediator, in this He is our Priest, in this the Sacrifice. Accordingly, when the apostle had exhorted us to present our bodies as a living sacrifice, holy, acceptable to God, our reasonable service, and not to be conformed to the world, but to be transformed in the renewing of our mind, so that we might discern what is that good, and acceptable, and perfect will of God, that is to say, the true sacrifice of ourselves, he says, “For I say, through the grace of God which is given to me, to every man that is among you, not to think of himself more highly than he ought to think, but to think soberly, as God has dealt to every man the measure of faith. For, as we have many members in one body, and not all members have the same function, so we, being many, are one body in Christ, and each of us members of one another, having gifts differing according to the grace that is given to us.” Romans 12:3-6 This is the sacrifice of Christians: we, being many, are one body in Christ. And this also is the sacrifice which the Church continually celebrates in the sacrament of the altar, known to the faithful, in which she teaches that she herself is offered in the offering she makes to God.