“Perhaps some may ask, "Ought we not then to
inquire what is the will of God in all things? And ought not His will to be the rule of our practice?" Unquestionably it ought. But how is a sober Christian to make this inquiry? To know what is the will of God? Not by waiting for supernatural dreams; not by expecting God to reveal it in visions; not by looking for any particular impressions or sudden impulses on his mind: no; but by consulting the oracles of God. "To the law and to the testimony!" This is the general method of knowing what is "the holy and acceptable will of God."
23. "But how shall I know what is the will of God, in such and such a particular case? The thing proposed is, in itself, of an indifferent nature, and so left undetermined in Scripture." I answer, the Scripture itself gives you a general rule. applicable to all particular cases: "The will of God is our sanctification." It is His will that we should be inwardly and outwardly holy; that we should be good, and do good, in every kind and in the highest degree whereof we are capable. Thus far we tread upon firm ground. This is as clear as the shining of the sun. In order, therefore, to know what is the will of God in a particular case, we have only to apply this general rule.
24. Suppose, for instance, it were proposed to a reasonable man to marry, or to enter into a new business: in order to know whether this is the will of God, being assured, "It is the will of God concerning me, that I should be as holy and do as much good as I can," he has only to enquire, "In which of these states can I be most holy, and do the most good?" And this is to be determined, partly by reason, and partly by experience. Experience tells him what advantages he has in his present state, either for being or doing good; and reason is to show, what he certainly or probably will have in the state proposed. By comparing these, he is to judge which of the two may most conduce to his being and doing good; and as far as he knows this, so far he is certain what is the will of God.
25. Meantime, the assistance of His Spirit is supposed, during the whole process of the inquiry. Indeed it is not easy to say, in how many ways that assistance is conveyed. He may bring many circumstances to our remembrance; may place others in a stronger and clearer light; may insensibly open our mind to receive conviction, and fix that conviction upon our heart. And to a concurrence of many circumstances of this kind, in favour of what is acceptable in His sight, He may superadd such an unutterable peace of mind, and so uncommon a measure of His love, as will leave us no possibility of doubting, that this, even this, is His will concerning us.
26. This is the plain, scriptural, rational way to know what is the will of God in a particular case. But considering how seldom this way is taken, and what a flood of enthusiasm must needs break in on those who endeavour to know the will of God by unscriptural, irrational ways; it were to be wished that the expression itself were far more sparingly used. The using it, as some do, on the most trivial occasions, is a plain breach of the third commandment. It is a gross way of taking the name of God in vain, and betrays great irreverence toward Him. Would it not be far better, then, to use other expressions, which are not liable to such objections? For example: instead of saying, on any particular occasion, "I want to know what is the will of God;" would it not be better to say, "I want to know what will be most for my improvement; and what will make me most useful?" This way of speaking is clear and unexceptionable: it is putting the matter on a plain, scriptural issue, and that without any danger of enthusiasm.”
from Wesley's Sermon #37 – The Nature of Enthusiasm.
(text from the 1872 edition - Thomas Jackson, editor)