The fellowship of prayer and faith is perfected in the fellowship of love. This love is love towards one another and for one another; it is the strong consciousness that we are bound to one another in prosperity and in misfortune, not merely by natural bonds, but by a supernatural kinship through communion in the Body and Blood of Christ, our Head. This love produces a feeling of mutual responsibility in sorrow and in joy, a warm sympathy, a magnanimous generosity, an absolute loyalty of service to others, as St. Paul so beautifully depicts it (1 Cor. xiii). This love is that solidarity of Christian sentiment which ever first envisages the whole and comes back to the individual and to itself only from the whole; which with deep reverence of soul sees in every member of Christ, even in the least, a brother or sister of the Lord, yes, Christ Himself. This love is the most precious fruit of the Communion of the Saints on earth. It is this love that gives to the external and visible organism of the Body of Christ, to papacy and episcopacy, the vital inspiration of Christ (see p. 42 ff.) and it is this alone that creates and maintains its inner wealth. In truth and in fact this love is therefore the lifeblood of the Body of Christ, which, welling forth out of the heart of the God-man, flows through the whole Body and gives it form and strength and beauty. Without this love the Body of Christ on earth would be a rigid corpse, and all Church ordinances and offices, all sacraments, all dogmas, all faith would be stale and unprofitable, like sounding brass or tinkling cymbal,” or, in the words of St. Augustine, mere “forms of piety.” Moreover the inner history of the Body of Christ, the course of its ills and difficulties, of its progress and development, is determined by the sincerity, inwardness and fertility of this love. There is no more perilous crisis for it than when its love is in jeopardy. When it can no longer be said of the majority of its members: “See how these Christians love one another!” then will be the most dangerous crisis of all, that time when, in our Lord’s words, “the charity of many shall grow cold” (Matt. xxiv, 12) For there is nothing so essentially alien to the Body of Christ, nothing so inimical, as that its members should abandon their mutual love. For Christ our Lord is the incarnate revelation of God’s love, nor is the Body of Christ anything else but the implanting and growth of that same love, in all those who are incorporated into Christ. Wherever Christianity is, there is love. According to St. Augustine’s striking saying, love is the motive weight of the Christian being.[7] It can be manifested nowhere else in such purity, inwardness and power as in Christ and His Body. And so the development of the Body of Christ on earth is characterized by nothing so plainly as by the growth of this love. All development of dogma, of worship, of government and of law, is profitable to the Body of Christ only because it produces this growth of love. And the Body of Christ will not be fully mature and perfect, until love, as the soul of all the virtues (forma virtutum), has become not merely in some members but in all, both in the shepherd and in the flock, the fundamental and dominant principle of all living, suffering and dying. By no other mark shall men know that they are the disciples of Christ than by this, that they have love one to another.