Differing Natures

Sane quoniam te novi, accipe hoc quiddam grande et breve. Est natura per locos et tempora mutabilis, ut corpus. Et est natura per locos nullo modo, sed tantum per tempora etiam ipsa mutabilis, ut anima. Et est natura quae nec per locos, nec per tempora mutari potest; hoc Deus est. Quod hic insinuavi quoque modo mutabile, creatura dicitur; quod immutabile, Creator. Cum autem omne quod esse dicimus, in quantum manet dicamus, et in quantum unum est, omnis porro pulchritudinis forma unitas sit: vides profecto in ista distributione naturarum, quid summe sit, quid infime, et tamen sit; qui medie, maiusque infimo, et minus summo sit. Summum illud est ipsa beatitas: infimum, quod nec beatum esse potest, nec miserum: quod vero medium, vivit inclinatione ad infimum, misere; conversione ad summum, beate vivit. Qui Christo credit, non diligit infimum, non superbit in medio, atque ita summo inhaerere fit idoneus: et hoc est totum quod agere iubemur, monemur, accendimur. Sanctus Augustinus Hipponensis, ex Epistula XVIII, Caelestino

Since I know you well, receive these short and grand themes. There is a nature through time and place which is mutable, that is, the corporeal. There is nature which is mutable not in respect to place but only in respect of time, namely, that is, the spiritual. And there is a third nature which  is mutable neither in respect of place time, that is, God. Those natures of which I have said that they are somehow mutable are called creatures and that which is immutable is the Creator. When we speak of thing existing it is in as much as it persists and is one, and so unity is the form of every beauty, you certainly see in this classification of natures, which exists in the highest sense, and which occupies the lowest, yet is, and which occupies the middle place, greater than the lowest, but less than the highest. That highest is blessedness itself, the lowest is that which cannot be either blessed or wretched, and the intermediate nature when it stoops towards the lowest lives in wretchedness, and turning toward the highest in blessedness. He who believes in Christ does not seek the lowest, is not proud in that which is intermediate, and thus he is fit to adhere to that which is highest; and this is all that we are commanded, admonished, and inspired to do. Saint Augustine of Hippo, from Letter 18, To Caelestinus