There is a twofold understanding or knowledge of good that God has made the mind of man capable of.  The first, that which is merely speculative and notional; as when a person only speculatively judges that anything is, which, by the agreement of mankind, is called good or excellent, viz., that which is most to general advantage, and between which and a reward there is a suitableness, and the like.  And the other is, that which consists in the sense of the heart:  as when there is a sense of the beauty, amiableness, or sweetness of a thing; so that the heart is sensible of pleasure and delight in the presence of the idea of it.  In the former is exercised merely the speculative faculty, or the understanding, strictly so called, or as spoken of in distinction from the will or disposition of the soul.  In the latter, the will, or inclination, or heart is mainly concerned.

Thus there is a difference between having an opinion that God is holy and gracious, and having a sense of the loveliness and beauty of that holiness and grace.  There is a difference between having a rational judgment that honey is sweet, and having a sense of its sweetness.  A man may have the former that knows not how honey tastes; but a man can not have the latter unless he has an idea of the taste of honey in his mind.  So there is a difference between believing that a person is beautiful and having a sense of his beauty.  The former may be obtained by hearsay, but the latter only by seeing the countenance.  There is a wide difference between mere speculative rational judging anything to be excellent, and having a sense of its sweetness and beauty.  The former rests only in the head, speculation only is concerned in it; but the heart is concerned in the latter.  When the heart is sensible of the beauty and amiableness of a thing, it necessarily feels pleasure in the apprehension.  It is implied in a person’s being heartily sensible of the loveliness of a thing, that the idea of it is sweet and pleasant to his soul; which is a far different thing from having a rational opinion that it is excellent.

2.  There arises from this sense of divine excellency of things contained in the word of God a conviction of the truth and reality of them; and that either directly or indirectly.

First, indirectly, and that two ways.

(1) As the prejudices that are in the heart, against the truth of divine things, are hereby removed; so that the mind becomes susceptive of the due force of rational arguments for their truth.  The mind of man is naturally full of prejudices against the truth of divine things:  it is full of enmity against the doctrines of the gospel; which is a disadvantage to those arguments that prove their truth, and causes them to lose their force upon the mind.  But when a person has discovered to him the divine excellency of Christian doctrines, this destroys the enmity, removes those prejudices, and sanctifies the reason, and causes it to lie open to the force of arguments for their truth.