Francis de Sales, Treatise on the Love of God

If there could be found any men who were in the integrity of original justice in which Adam was created, though otherwise not helped by another assistance from God than that which he affords to each creature, in order that it may be able to do the actions befitting its nature, such men would not only have an inclination to love God above all things 57but even naturally would be able to put into execution so just an inclination. For as this heavenly author and master of nature co-operates with and lends his strong hand to fire to spring on high, to water to flow towards the sea, to earth to sink down to its centre and stay there—so having himself planted in man's heart a special natural inclination not only to love good in general but to love in particular and above all things his divine goodness which is better and sweeter than all things—the sweetness of his sovereign providence required that he should contribute to these blessed men of whom we speak as much help as should be necessary to practise and effectuate that inclination. This help would be on the one hand natural, as being suitable to nature, and tending to the love of God as author and sovereign master of nature, and on the other hand it would be supernatural, because it would correspond not with the simple nature of man, but with nature adorned, enriched and honoured by original justice, which is a supernatural quality proceeding from a most special favour of God. But as to the love above all things which such help would enable these men to practise, it would be called natural, because virtuous actions take their names from their objects and motives, and this love of which we speak would only tend to God as acknowledged to be author, lord and sovereign of every creature by natural light only, and consequently to be amiable and estimable above all things by natural inclination and tendency.

And although now our human nature be not endowed with that original soundness and righteousness which the first man had in his creation, but on the contrary be greatly depraved by sin, yet still the holy inclination to love God above all things stays with us, as also the natural light by which we see his sovereign goodness to be more worthy of love than all things; and it is impossible that one thinking attentively upon God, yea even by natural reasoning only, should not feel a certain movement of love which the secret inclination of our nature excites in the bottom of our hearts, by which at the first apprehension of this chief and sovereign object, the will is taken, and perceives itself stirred up to a complacency in it.

It happens often amongst partridges that one steals away 58another's eggs with intention to sit on them, whether moved by greediness to become a mother, or by a stupidity which makes them mistake their own, and behold a strange thing, yet well supported by testimony!—the young one which was hatched and nourished under the wings of a stranger partridge, at the first call of the true mother, who had laid the egg whence she was hatched, quits the thief-partridge, goes back to the first mother, and puts herself in her brood, from the correspondence which she has with her first origin. Yet this correspondence appeared not, but remained secret, shut up and as it were sleeping in the bottom of nature, till it met with its object; when suddenly excited, and in a sort awakened, it produces its effect, and turns the young partridge's inclination to its first duty. It is the same, Theotimus, with our heart, which though it be formed, nourished and bred amongst corporal, base and transitory things, and in a manner under the wings of nature, notwithstanding, at the first look it throws on God, at its first knowledge of him, the natural and first inclination to love God which was dull and imperceptible, awakes in an instant, and suddenly appears as a spark from amongst the ashes, which touching our will gives it a movement of the supreme love due to the sovereign and first principle of all things.