Christianity as a specific doctrine was slain with Jesus, suddenly and utterly. He was hardly cold in his grave, or high in his heaven (as you please), before the apostles dragged the tradition of him down to the level of the thing it has remained ever since.
The holy heaven yearns to wound the earth, and yearning layeth hold on the earth to join in wedlock; the rain, fallen from the amorous heaven, impregnates the earth, and it bringeth forth for mankind the food of flocks and herds and Demeter's gifts; and from that moist marriage-rite the woods put on their bloom.
As to those other things which we hold on the authority, not of Scripture, but of tradition, and which are observed throughout the whole world, it may be understood that they are held as approved and instituted either by the apostles themselves, or by plenary Councils, whose authority in the Church is most useful, e.g. the annual commemoration, by special solemnities, of the Lord's passion, resurrection, and ascension, and of the descent of the Holy Spirit from heaven, and whatever else is in like manner observed by the whole Church wherever it has been established.
We don't understand that life is heaven, for we have only to understand that and it will at once be fulfilled in all its beauty, we shall embrace each other and weep.