Sensus Divinantis by John Calvin,
To prevent anyone from taking refuge in the pretense of ignorance, God himself has implanted in all men a certain understanding of his divine majesty. Ever renewing its memory, he repeatedly sheds fresh drops. Since, therefore, men one and all perceive that there is a God and that he is their Maker, they are condemned by their own testimony because they have failed to honor him and to consecrate their lives to his will.
Men of sound judgment will always be sure that a sense of divinity which can never be effaced is engraven upon men’s minds. Indeed, the perversity of the impious, who though they struggle furiously are unable to extricate themselves from the fear of God, is abundant testimony that this conviction, namely that there is some God, is naturally inborn in all, and is fixed deep within, as it were in the very marrow … For the world…, tries as far as it is able to cast away all knowledge of God, and by every means to corrupt the worship of him. I only say that though the stupid hardness in their minds, which the impious eagerly conjure up to reject God, wastes away, yet the sense of divinity, which they greatly wished to have extinguished, thrives and presently burgeons. From this we conclude that it is not a doctrine that must first be learned in school, but one of which each of us is master from his mother’s womb and which nature itself permits none to forget, although many strive with every nerve to this end.
Institutes of the Christian Religion, 1:3.1