Now it is but a parallel exercise of reasoning to interpret the previous history of a doctrine by its later development, and to consider that it contains the later _in posse_ and in the divine intention; and the grudging and jealous temper, which refuses to enlarge the sacred text for the fulfilment of prophecy, is the very same that will occupy itself in carping at the Ante-nicene testimonies for Nicene or Medieval doctrines and usages. When "I and My Father are One" is urged in proof of our Lord's unity with the Father, heretical disputants do not see why the words must be taken to denote more than a unity of will. When "This is My Body" is alleged as a warrant for the change of the Bread into the Body of Christ, they explain away the words into a figure, because such is their most obvious interpretation. And, in like manner, when Roman Catholics urge St. Gregory's invocations, they are told that these are but rhetorical; or St. Clement's allusion to Purgatory, that perhaps it was Platonism; or Origen's language about praying to Angels and the merits of Martyrs, that it is but an instance of his heterodoxy; or St. Cyprian's exaltation of the _Cathedra Petri_, that he need not be contemplating more than a figurative or abstract see; or the general testimony to the spiritual authority of Rome in primitive times, that it arose from her temporal greatness; or Tertullian's language about Tradition and the Church, that he took a lawyer's view of those subjects; whereas the early condition, and the evidence, of each doctrine respectively, ought consistently to be interpreted by means of that development which was ultimately attained. 8.