"Man reaches the highest point of his knowledge about God when he knows that he knows him not, inasmuch as he knows that that which is God transcends whatsoever he conceives of him."

"It is on account neither of God's weakness nor ignorance that evil comes into the world, but rather it is due to the order of his wisdom and the greatness of his goodness that diverse grades of goodness occur in things, many of which would be lacking if no evil were permitted. Indeed, the good of patience would not exist without the evil of persecution; nor the good of preservation of life in a lion if not for the evil of the destruction of the animals on which it lives."

"Now what has been said about the Jews is also to be understood about Cahorsins, and anyone else depending upon the depravity of usury."

"It would be better if they [rulers] compelled the Jews to work for their living, as they do in parts of Italy, than that, living without occupation, they can grow rich only by usury (solis usuris ditentur)."

"Since the Jews may not licitly keep those things which they have extorted from others through usury, the consequence is also that if you [rulers] receive these things from them, neither may you licitly keep them.[…] You should restore them to those to whom the Jews themselves are morally bound to make restitution."

"To become like God is the ultimate end of all."

"The highest perfection of human life consists in the mind of man being detached from care, for the sake of God."

"Natural inclinations are present in things from God, who moves all things. So it is impossible for the natural inclinations of a species to be toward evil in itself. But there is in all perfect animals a natural inclination toward carnal union. Therefore it is impossible for carnal union to be evil in itself."

"The perfection of the effect demonstrates the perfection of the cause, for a greater power brings about a more perfect effect. But God is the most perfect agent. Therefore, things created by Him obtain perfection from Him. So, to detract from the perfection of creatures is to detract from the perfection of divine power."

"For creation is not a change, but that dependence of the created existence on the principle from which it is instituted, and thus is of the genus of relation; whence nothing prohibits it being in the created as in the subject. Creation is thus said to be a kind of change, according to the way of understanding, insofar as our intellect accepts one and the same thing as not existing before and afterwards existing."

"Muhammad seduced the people by promises of carnal pleasure to which the concupiscence of the flesh goads us. His teaching also contained precepts that were in conformity with his promises, and he gave free rein to carnal pleasure. In all this, as is not unexpected, he was obeyed by carnal men. As for proofs of the truth of his doctrine, he brought forward only such as could be grasped by the natural ability of anyone with a very modest wisdom. Indeed, the truths that he taught he mingled with many fables and with doctrines of the greatest falsity. He did not bring forth any signs produced in a supernatural way, which alone fittingly gives witness to divine inspiration; for a visible action that can be only divine reveals an invisibly inspired teacher of truth. On the contrary, Muhammad said that he was sent in the power of his arms—which are signs not lacking even to robbers and tyrants. What is more, no wise men, men trained in things divine and human, believed in him from the beginning, Those who believed in him were brutal men and desert wanderers, utterly ignorant of all divine teaching, through whose numbers Muhammad forced others to become his followers by the violence of his arms. Nor do divine pronouncements on the part of preceding prophets offer him any witness. On the contrary, he perverts almost all the testimonies of the Old and New Testaments by making them into fabrications of his own, as can be seen by anyone who examines his law. It was, therefore, a shrewd decision on his part to forbid his followers to read the Old and New Testaments, lest these books convict him of falsity. It is thus clear that those who place any faith in his words believe foolishly."

"Truth is the ultimate end of the whole universe."

"We can open our hearts to God, but only with Divine help."

"Nothing is in the intellect that was not first in the senses."

"The greatness of the human being consists in this: that it is capable of the universe."

"One who liberates his country by killing a tyrant is to be praised and rewarded."

"With regard to the abuse of authority, this also may come about in two ways. First, when what is ordered by an authority is opposed to the object for which that authority was constituted (if, for example, some sinful action is commanded or one which is contrary to virtue, when it is precisely for the protection and fostering of virtue that authority is instituted). In such a case, not only is there no obligation to obey the authority, but one is obliged to disobey it, as did the holy martyrs who suffered death rather than obey the impious commands of tyrants. Secondly, when those who bear such authority command things which exceed the competence of such authority; as, for example, when a master demands payment from a servant which the latter is not bound to make, and other similar cases. In this instance the subject is free to obey or disobey."

"The order of authority derives from God, as the Apostle says [in Romans 13:1-7]. For this reason, the duty of obedience is, for the Christian, a consequence of this derivation of authority from God, and ceases when that ceases. But, as we have already said, authority may fail to derive from God for two reasons: either because of the way in which authority has been obtained, or in consequence of the use which is made of it. There are two ways in which the first may occur. Either because of a defect in the person, if he is unworthy; or because of some defect in the way itself by which power was acquired, if, for example, through violence, or simony or some other illegal method."

"Anima mea non est ego."

"Jesus Christ: Bene scripsísti de me, Thoma; quam ergo mercédem accípies? Aquinas: Non áliam, Dómine, nisi teípsum."

"Raynalde, non possum, quia omnia quae scripsi videntur mihi palae. Replying to Reginald of Piperno: Videntur mihi palae respectu eorum quae vidi et revelata sunt mihi."

"Omne verum a quocumque dicatur a Spiritu Sancto est."

"A hymn is the praise of God with song; a song is the exultation of the mind dwelling on eternal things, bursting forth in the voice."