The author distinguishes the faith from the errors of Pagans, Or “Gentiles.” The Christians regarded themselves as placed in the world much as the Hebrews had been planted in the midst of the “nations round about.” Jews, and Heretics, and after explaining the significance of the names “God” and “Lord,” shows clearly the difference of Persons in Unity of Essence. The Latin word is natura, which, at first sight, seems less abstruse and metaphysical than the Greek οὐσία, or ὑπόστασις, or the Latin essentia and substantia, though it is not really so. A man’s natura, nature, is what he is at and from the beginning; “change of nature” means not an absolute change, but a reformation, a new guidance and treatment of tendencies, passions, powers—some receiving a precedence denied them before, others being suppressed and put in subjection. So God’s “nature” is what He is from and to all eternity, in Himself, unchangingly and unchangeably.  In dividing the Essence, the Arians not only bring in the doctrine of three Gods, but even overthrow the dominion of the Trinity.