"Strictly speaking, there are no 'cardinal' virtues in Christianity, for Christian character does not 'hinge' round the disciplined practice of virtue: it is a spontaneous growth, it is a crop of qualities springing from the seed of new life divinely sown . . .; or--more characteristically described--it is life in the new age, resulting from incorporation in the new humanity which is Christ . . . . Agape is not a virtue among other virtues so much as an impulse, divinely implanted: it is God's love for us in Christ, reflected and responded to. And what in other systems might be called virtues are the shape spontaneously taken by agape in the Christian community . . . . Therefore, although in fact many Christian qualities seem to coincide with those on the Stoic list, the difference is a radical one. The Stoic virtues are the proud struggle of the human spirit to conform to nature and to gain the mastery over weakness; the Christian virtues emerge after the recognition of sin and the confession of human helplessness: they are the result of committal to God and dependence upon him" (193-4).
"In the last analysis, it is questionable, indeed, whether a Christian ethical system, as such, can exist. Christianity is concerned with the transformation, in Christ, of personal relations. The code which provides a framework or scaffolding within which this operates must, strictly speaking, be a borrowed one, for Christianity, as such, does not offer a distinctive code or system of conduct" (274).
C.F.D. Moule, The Birth of the New Testament (3rd ed.; Harper & Row, 1982).