Glossa Ordinaria

(ap. Anselm.) It is to be observed, that the mystery of the second regeneration, that, to wit, which shall be in the resurrection, when the flesh shall be raised again, agrees well with the mystery of the first which is in baptism, when the soul is raised again. For in the baptism of Christ is shewn the working of the whole Trinity; there was the Son incarnate, the Holy Ghost appealing in the figure of a dove, and the Father made known by the voice. In like manner in the transfiguration, which is the sacrament of the second regeneration, the whole Trinity appeared; the Father in the voice, the Son in the man, and the Holy Spirit in the cloud. It is made a question how the Holy Spirit was shewn there in the dove, here in the cloud. Because it is His manner to mark His gifts by specific outward forms. And the gift of baptism is innocence, which is denoted by the bird of purity. But as in the resurrection, He is to give splendour and refreshment, therefore in the cloud are denoted both the refreshment and the brightness of the rising bodies. It follows, And when the disciples heard it, they fell on their faces, and feared greatly.