From Religious Affections

From Edwards, Jonathan. A Treatise Concerning Religious Affections. The Works of Jonathan Edwards. Vol. 1, Peabody, MA: Hendrickson Publishers. 2004.

If we be not in good earnest: in religion, and our wills and inclinations be not strongly exercised, we are nothing. The things of religion are so great, that there can be no suitableness in the exercises of our hearts, to their nature and importance, unless they be lively and powerful. In nothing is vigour in the actings of our inclinations so requisite, as in religion; and in nothing is lukewarmness so odious. True religion is evermore a powerful thing; and the power of it appears, in the first place, in its exercises in the heart, its principal and original seat. Hence true religion is called the power of godliness, in distinction from external appearances, which are the form of it, 2 Tim. iii. 5. "Having a form of godliness, but denying the power of it." The Spirit of God, in those who have sound solid religion, is a Spirit of powerful holy affection; and therefore, God is said "to have given them the Spirit of power, and of love, and of a sound mind," (2 Tim. i. 7.) And such, when they receive the Spirit of God in his sanctifying and saving influences, are said to be "baptized with the Holy Ghost, and with fire;" By reason of the power and fervour of those exercises which the Spirit of God excites in them, and whereby their hearts, when grace is in exercise, may be said to burn within them. (Luke xxiv. 32.)
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And the duty of singing praises to God, seems to be appointed wholly to excite and express religious affections. No other reason can be assigned, why we should express ourselves to God in verse, rather than in prose, and do it with music, but only, that such is our nature and frame and that these things have a tendency to move our affections.
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Upon the whole, I think it clearly and abundantly evident, that true religion lies very much in the affections. Not that I think these arguments prove, that religion in the hearts of the truly godly, is ever in exact proportion to the deree of affection and present emotion of the mind...The degree of religion is to be estimated by the fixedness and strength of habit exercised in affection, whereby holy affection is habitual rather than by the degree of the present exercise:
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If we ought ever to exercise our affections at all, and if the Creator has not unwisely constituted the human nature in making these principles part of it, then they ought to be exercised about those objects which are most worthy of them.