1. The knowledge of God being manifested to all makes the reprobate without excuse. Universal belief and acknowledgement of the existence of God.
2. Objection -- that religion and the belief of a Deity are the inventions of crafty politicians. Refutation of the objection. This universal belief confirmed by the examples of wicked men and Atheists.
3. Confirmed also by the vain endeavours of the wicked to banish all fear of God from their minds. Conclusion, that the knowledge of God is naturally implanted in the human mind.
1. That there exists in the human minds and indeed by natural instinct, some sense of Deity, we hold to be beyond dispute, since God himself, to prevent any man from pretending ignorance, has endued all men with some idea of his Godhead, the memory of which he constantly renews and occasionally enlarges, that all to a man being aware that there is a God, and that he is their Maker, may be condemned by their own conscience when they neither worship him nor consecrate their lives to his service. Certainly, if there is any quarter where it may be supposed that God is unknown, the most likely for such an instance to exist is among the dullest tribes farthest removed from civilisation. But, as a heathen tells us,  there is no nation so barbarous, no race so brutish, as not to be imbued with the conviction that there is a God. Even those who, in other respects, seem to differ least from the lower animals, constantly retain some sense of religion; so thoroughly has this common conviction possessed the mind, so firmly is it stamped on the breasts of all men. Since, then, there never has been, from the very first, any quarter of the globe, any city, any household even, without religion, this amounts to a tacit confession, that a sense of Deity is inscribed on every heart. Nay, even idolatry is ample evidence of this fact. For we know how reluctant man is to lower himself, in order to set other creatures above him. Therefore, when he chooses to worship wood and stone rather than be thought to have no God, it is evident how very strong this impression of a Deity must be; since it is more difficult to obliterate it from the mind of man, than to break down the feelings of his nature, -- these certainly being broken down, when, in opposition to his natural haughtiness, he spontaneously humbles himself before the meanest object as an act of reverence to God.
2. It is most absurd, therefore, to maintain, as some do, that religion was devised by the cunning and craft of a few individuals, as a means of keeping the body of the people in due subjection, while there was nothing which those very individuals, while teaching others to worship God, less believed than the existence of a God. I readily acknowledge, that designing men have introduced a vast number of fictions into religion, with the view of inspiring the populace with reverence or striking them with terror, and thereby rendering them more obsequious; but they never could have succeeded in this, had the minds of men not been previously imbued with that uniform belief in God, from which, as from its seed, the religious propensity springs. And it is altogether incredible that those who, in the matter of religion, cunningly imposed on their ruder neighbours, were altogether devoid of a knowledge of God. For though in old times there were some, and in the present day not a few are found who deny the being of a God, yet, whether they will or not, they occasionally feel the truth which they are desirous not to know. We do not read of any man who broke out into more unbridled and audacious contempt of the Deity than C. Caligula,  and yet none showed greater dread when any indication of divine wrath was manifested. Thus, however unwilling, he shook with terror before the God whom he professedly studied to condemn. You may every day see the same thing happening to his modern imitators. The most audacious despiser of God is most easily disturbed, trembling at the sound of a falling leaf. How so, unless in vindication of the divine majesty, which smites their consciences the more strongly the more they endeavour to flee from it. They all, indeed, look out for hiding-places where they may conceal themselves from the presence of the Lord, and again efface it from their mind; but after all their efforts they remain caught within the net. Though the conviction may occasionally seem to vanish for a moment, it immediately returns, and rushes in with new impetuosity, so that any interval of relief from the gnawing of conscience is not unlike the slumber of the intoxicated or the insane, who have no quiet rest in sleep, but are continually haunted with dire horrific dreams. Even the wicked themselves, therefore, are an example of the fact that some idea of God always exists in every human mind.
3. All men of sound Judgment will therefore hold, that a sense of Deity is indelibly engraven on the human heart. And that this belief is naturally engendered in all, and thoroughly fixed as it were in our very bones, is strikingly attested by the contumacy of the wicked, who, though they struggle furiously, are unable to extricate themselves from the fear of God. Though Diagoras,  and others of like stamps make themselves merry with whatever has been believed in all ages concerning religion, and Dionysus scoffs at the Judgment of heaven, it is but a Sardonian grin; for the worm of conscience, keener than burning steel, is gnawing them within. I do not say with Cicero, that errors wear out by age, and that religion increases and grows better day by day. For the world (as will be shortly seen) labours as much as it can to shake off all knowledge of God, and corrupts his worship in innumerable ways. I only say, that, when the stupid hardness of heart, which the wicked eagerly court as a means of despising God, becomes enfeebled, the sense of Deity, which of all things they wished most to be extinguished, is still in vigour, and now and then breaks forth. Whence we infer, that this is not a doctrine which is first learned at school, but one as to which every man is, from the womb, his own master; one which nature herself allows no individual to forget, though many, with all their might, strive to do so. Moreover, if all are born and live for the express purpose of learning to know God, and if the knowledge of God, in so far as it fails to produce this effect, is fleeting and vain, it is clear that all those who do not direct the whole thoughts and actions of their lives to this end fail to fulfil the law of their being. This did not escape the observation even of philosophers. For it is the very thing which Plato meant (in Phoed. et Theact.) when he taught, as he often does, that the chief good of the soul consists in resemblance to God; i.e., when, by means of knowing him, she is wholly transformed into him. Thus Gryllus, also, in Plutarch (lib. guod bruta anim. ratione utantur), reasons most skilfully, when he affirms that, if once religion is banished from the lives of men, they not only in no respect excel, but are, in many respects, much more wretched than the brutes, since, being exposed to so many forms of evil, they continually drag on a troubled and restless existence: that the only thing, therefore, which makes them superior is the worship of God, through which alone they aspire to immortality.
 "Intelligi necesse est deos, quoniam insitas eorum vel potius innatas cognitiones habemus.--Quae nobis natura informationem deorum ipsorum dedit, eadem insculpsit in mentibus ut eos aeternos et beatos haberemus."--Cic. de Nat. Deor. lib. 1 c. 17.--"Itaque inter omnes omnium gentium summa constat; omnibus enim innatum est, et in animo quasi insculptum esse deos."--Lib. 2. c. 4. See also Lact. Inst. Div. lib. 3 c. 10.  Suet. Calig. c. 51.  Cic. De Nat. Deor. lib. 1 c. 23. Valer. Max. lib. 1. c. 1.
 Suet. Calig. c. 51.
 Cic. De Nat. Deor. lib. 1 c. 23. Valer. Max. lib. 1. c. 1.