The Fathers of the Church again and again extol the deification (_deificatio_, θείωσις) of man effected by sanctifying grace and compare the union of the soul with God to the commingling of water with wine, the penetration of iron by fire, etc. St. Athanasius(1025) begins his Christological teaching with the declaration: “He was not, therefore, first man and then God, but first God and then man, in order that He might rather deify us.”(1026) St. Augustine describes the process of deification as follows: “He justifies who is just of Himself, not from another; and He deifies who is God of Himself, not by participation in another. But He who justifies also deifies, because He makes [men] sons of God through justification.... We have been made sons of God and gods; but this is a grace of the adopting [God], not the nature of the progenitor. The Son of God alone is God; ... the others who are made gods are made gods by His grace; they are not born of His substance, so as to become that which He is, but in order that they may come to Him by favor and become co-heirs with Christ.”(1027) The idea underlying this passage has found its way into the liturgy of the Mass,(1028) and Ripalda is justified in declaring that it cannot be denied without rashness.(1029) b) In trying to explain in what manner grace enables us to partake of the divine nature, it is well to keep in view the absolutely supernatural character of sanctifying grace and the impossibility of any deification of the creature in the strict sense of the term. The truth lies between these two extremes. A few medieval mystics(1030) and modern Quietists(1031) were guilty of exaggeration when they taught that grace transforms the human soul into the substance of the Godhead, thus completely merging the creature in its Creator. This contention(1032) leads to Pantheism. How can the soul be merged in the Creator, since it continues to be subject to concupiscence? “We have therefore,” says St. Augustine, “even now begun to be like Him, as we have the first-fruits of the Spirit; but yet even now we are unlike Him, by reason of the old nature which leaves its remains in us. In as far, then, as we are like Him, in so far are we, by the regenerating Spirit, sons of God; but in as far as we are unlike Him, in so far are we the children of the flesh and of this world.”(1033)