Jonathan Edwards’s The Religious Affections is considered one of the great classics of evangelical literature. (You can access the entire critical edition from Yale University Press online for free.)
Edwards’s is that ”True religion, in great part, consists in holy affections” (95).
Edwards believed the soul has two faculties: (1) the understanding (by which the soul perceives, speculates, discerns, views, judges things); and (2) the inclination or will (by which the soul is inclined or disinclined, pleased or displeased, approves or rejects).
The affections have to do with the second faculty. Affections, according to Edwards, are “the more vigorous and sensible exercises of the inclination and will of the soul” (96).
Edwards seeks to show that the Bible makes true affections an essential part of godliness: “They would deny that much of true religion lies in the affections, and maintain the contrary, must throw away what we have been wont to own for our Bible, and get some other rule, by which to judge of the nature of religion” (106).
But not all affections are created equal. Some are to be rejected and put to death while others are to be approved and cultivated: “The right way, is not to reject all affections, nor to approve all; but to distinguish between affections, approving some, and rejecting others; separating between the wheat and the chaff, the gold and the dross, the previous and the vile” (121). His book is an attempt to help us do precisely that.
In the second part of the book, Edwards works through twelve “signs” that are uncertain. In other words, he explains twelve things that may look like indicators of truly gracious affections, but which do not prove things one way or the other:
No Sign 1. The religious affections are very great, or raised very high. (127-31)
No Sign 2. They have great effects on the body. (131-35)
No Sign 3. They cause those who have them, to be fluent, fervent and abundant, in talking of the things of religion. (135-37)
No Sign 4. Persons did make ’em themselves, or excite ’em of their own contrivance, and by their own strength. (138-42)
No Sign 5. They come with texts of Scripture, remarkably brought to the mind. (142-45)
No Sign 6. There is an appearance of love in them. (146-47)
No Sign 7. Persons having religious affections of many kinds, accompanying one another, is not sufficient to determine whether they have any gracious affections or no. (147-51)
No Sign 8. Comforts and joys seem to follow awakenings and convictions of conscience, in a certain order. (151-63)
No Sign 9. They dispose persons to spend much time in religion, and to be zealously engaged in the external duties of worship. (163-65)
No Sign 10. They much dispose persons with their mouths to praise and glorify God. (165-67)
No Sign 11. They make persons that have them, exceedingly confident that what they experience is divine, and that they are in a good estate. (167-81)
No Sign 12. The outward manifestations of them, and the relation persons give of them, are very affecting and pleasing to the truly godly, and such as greatly gain their charity, and win their hearts. (181-90)
Then in the third part, Edwards sets forth twelve true signs—those things which distinguish the truly gracious and holy affections as being part of true religion:
True Sign 1. Arise from those influences and operations on the heart, which are spiritual, supernatural, and divine. (197-239)
True Sign 2. Objectively grounded in the transcendently excellent and amiable nature of divine things, as they are in themselves (and not in any conceived relation they bear to self or self-interest). (240-52)
True Sign 3. Primarily founded on the loveliness of the moral excellency of divine thing; a love to divine things for the beauty and sweetness of their moral excellency is the first beginning and spring of all holy affections. (253-65)
True Sign 4 Arise from the mind’s being enlightened, rightly and spiritually to understand or apprehend divine things. (266-90)
True Sign 5. Attended with a reasonable and spiritual conviction of the judgment, of the reality and certainty of divine things. (291-310)
True Sign 6. Attended with evangelical humiliation (= a sense that a Christian has or his own utter insufficiency, despicableness, and odiousness, with an answerable frame of heart). (311-39)
True Sign 7. Attended with a change of nature. (340-43)
True Sign 8. Tend to, and are attended with, the lamblike, dovelike spirit and temper of Jesus Christ; they naturally beget and promote such a spirit of love, meekness, quietness, forgiveness, and mercy, as appeared in Christ. (344-356)
True Sign 9. Soften the heart and are attended to and followed with a Christian tenderness of spirit. (357-64)
True Sign 10. Have beautiful symmetry and proportion. (365-75)
True Sign 11. The higher gracious affections are raised, the more is a spiritual appetite and longing of soul after spiritual attainments increased. (376-82)
True Sign 12. Have their exercise and fruit in Christian practice. (383-462)
Some readers interested in exploring this great work may want to begin with Sam Storms’s excellent Signs of the Spirit: An Interpretation of Jonathan Edwards’ Religious Affections (Crossway, 2007), which works through all of the signs in a condensed and interpretive way.