Socrates
The first who directed the entire effort of philosophy to ethics, all who went before him having expended their greatest efforts in the investigation of nature. However, it cannot be certainly discovered whether Socrates did this because he was wearied of obscure and uncertain things, and so wished to direct his mind to the discovery of something manifest and certain, which was necessary in order to the obtaining of a blessed life, … or whether he did it because he was unwilling that minds defiled with earthly desires should essay to raise themselves upward to divine things. For he believed the causes of things to be ultimately reducible to nothing else than the will of the one true and supreme God, and they could only be comprehended by a purified mind.
It is evident, however, that he hunted out and pursued, with a wonderful pleasantness of style and argument, and with a most pointed and insinuating urbanity, the foolishness of ignorant men, who thought that they knew this or that,—sometimes confessing his own ignorance, and sometimes dissimulating his knowledge, even in those very moral questions to which he seems to have directed the whole force of his mind.
Plato
By birth, an Athenian of honorable parentage, he far surpassed his fellow-disciples in natural endowments, of which he was possessed in a wonderful degree. Yet, deeming himself and the Socratic discipline far from sufficient for bringing philosophy to perfection, he travelled as extensively as he was able, going to every place famed for the cultivation of any science of which he could make himself master. Thus he learned from the Egyptians, and the Pythagoreans -all the Italic philosophy which was then in vogue.
And, as he had a peculiar love for his master Socrates, he made him the speaker in all his dialogues, putting into his mouth whatever he had learned, either from others, or from the efforts of his own powerful intellect, tempering even his moral disputations with the grace and politeness of the Socratic style.
The Platonic Notion of God
In every changeable thing, the form which makes it that which it is, whatever be its mode or nature, can only be through Him who truly is, because He is unchangeable.
For to Him it is not one thing to be, and another to live, as though He could be, not living; nor is it to Him one thing to live, and another thing to understand, as though He could live, not understanding; nor is it to Him one thing to understand, another thing to be blessed, as though He could understand and not be blessed. But to Him to live, to understand, to be blessed, are to be. From this unchangeableness and this simplicity, all things must have been made by Him, and He could Himself have been made by none.
For there is no corporeal beauty, whether in the condition of a body, as figure, or in its movement, as in music, of which it is not the mind that judges. But this could never have been, had there not existed in the mind itself a superior form of these things, without bulk, without noise of voice, without space and time. But even in respect of these things, had the mind not been mutable, it would not have been possible for one to judge better than another with regard to sensible forms.
Since body and mind might be more or less beautiful in form, and, if they wanted form, they could have no existence, there is some existence in which is the first form, unchangeable, and therefore not admitting of degrees of comparison, and is the first principle of things which was not made, and by which all things were made.