(17) If any man will do his will, he shall know of the doctrine.--Better, If any man willeth to do His will, he shall know of the teaching. The stress is upon "willeth," which in our version reads as if it were only the auxiliary verb. It is not deed, which is the outcome of faith; but will, which precedes it, that is here spoken of. This human will to do the divine will is the condition of knowing it. The words are unlimited and far-reaching in their meaning. Those who heard them would naturally understand them, as it was intended they should, of the divine will expressed in the Law and the Prophets (John 7:19), but they include the will of God revealed, more or less clearly, to all men and in all times. Our thoughts dwell naturally on representative lives, such as those of Saul the Pharisee, Cornelius the centurion, Justin the philosopher; but the truth holds good for every honest heart in every walk of life. The "any man" of Christ's own words excludes none from its reach, and the voice of comfort and of hope is spoken alike to all in our ignorance, fears, doubts--that he who in very deed willeth to do God's will, shall not fail to know, now or in the life to come, of the teaching whether it be of God. (Comp. Notes on John 5:44 et seq., and John 6:29 and John 6:45.)

Verse 17. - The moral test is then applied to the great dictum which he had just uttered. If any man willeth - not merely desires, but performs the distinct act of willing - to do his will - as his will - he shall know; i.e. his intellectual faculty will be quickened into high activity by this moral and practical effort. If the Divine will concerning conduct meets the spontaneous act of the human will, if a man's will is set to fulfil the Divine will, to will and do what is revealed to him by God, the eye of the soul will be opened to see other things as well, and especially will have power to discern the all-pervading Divine element in this teaching of mine. He shall know concerning (περί) the teaching, whether it be of (ἐκ) God, or whether I speak from myself - from the simple ground of my own independent, self-taught humanity. The first and natural application of this mighty dictum and condition was a test by which the Jews might come at once to the understanding of his more than prophetic claim to teach - he having never learned in their rabbinical schools. It amounted to this: Your moral harmony with the will of God as already revealed to you will be the sure index and confirmation of the great fact I have just referred to. You will discern the Divine in my words, the absolutely true in my teaching. Here the Lord again refers to the great principle, "He that hath heard of the Father, and learned, cometh unto me;" "He that is of the truth heareth my voice." This moral submission to God will quicken all your powers to discern and come to an invincible assent as to my claims. This is not the deep subjective testimony of the inner intuition of those that already believe, by which a verbal assent becomes a fall consent, an unchangeable conviction, or "the full assurance of faith;" but it is addressed to unbelievers, and assures those who are bewildered by the novelty and sweep of his own words that, if they are set on doing the will of God, they will become perfectly satisfied that his own teaching, such as it is, is a stream of heavenly truth bursting from the very heart of God. The text has been cited by certain writers as the sum totel of the Christian revelation, almost as though it substituted practical obedience for true thinking, as though people might well be content with holy living, and might safely leave the decision of all difficult problems of thought and revelation to shift for themselves. Nothing could be further from its real meaning, either at the time or in any of its subsequent or universal applications. The solemn utterance has a wide outlook, and is constantly establishing its own verity. A profound and voluntary desire to do the will of God is the best preparation for intuitively perceiving the Divine authority of Christ and of his religion. The desire for holiness of principle and life sees in Christ not only the loftiest ideal of perfection, but the surest satisfaction to its conscious weakness, and casts itself upon his promises of saving power. The faith which is satisfied with Christ is not merely a conclusion drawn by logical processes from satisfactory premisses, it is the consequence of a new nature or a moral regeneration. In other words, it is the more practical and expanded form of the truth first of all addressed to Nicodemus, and also lying at the heart of the Beatitudes: "Except a man be born anew [from above], he cannot see the kingdom of God." If he is born again he will see it. "Blessed are the pure in heart: for they shall see God." "No man can come unto me except the Father, which hath sent me, draw him." The sentence presents the truth in a hopeful and positive form, and puts the criterion of the Divine informant within the reach of practical ethics. It is an appeal to the conscience as well as to the understanding. Apart from the subjective moral element, all other evidences of the presence of the Divine in nature, in history, in Christ, will be unimpressive and unimportant. A willingness to do the will of God is not a substitute for, but a condition of, true knowledge.

7:14-24 Every faithful minister may humbly adopt Christ's words. His doctrine is not his own finding out, but is from God's word, through the teaching of his Spirit. And amidst the disputes which disturb the world, if any man, of any nation, seeks to do the will of God, he shall know whether the doctrine is of God, or whether men speak of themselves. Only those who hate the truth shall be given up to errors which will be fatal. Surely it was as agreeable to the design of the sabbath to restore health to the afflicted, as to administer an outward rite. Jesus told them to decide on his conduct according to the spiritual import of the Divine law. We must not judge concerning any by their outward appearance, but by their worth, and by the gifts and graces of God's Spirit in them.If any man will do his will,.... Meaning, not one that perfectly fulfils the law, which is the good, and perfect, and acceptable will of God; for there is no man that does this, or can do it; nor is it so said here, "if any man do his will", but "if any man will do" it; that is, is desirous of doing it; who has it wrought in him both to will and do, of the good pleasure of God, by his grace and Spirit; with whom to will is present, though, he has not power to perform, and so is a spiritual man; and who believes in the Lord Jesus Christ, which is one branch of the will of God; and who depends upon the Spirit and grace of God, and acts from a principle of love to God, and in the exercise of faith on Christ:

he shall know of the doctrine, whether it be of God, or whether I speak of myself; not a man of mere natural knowledge and learning, or a man of theory and speculation, is a judge of doctrine; but he that leans not to his own understanding, and implores the assistance of the Divine Spirit, and who is for reducing doctrine into practice: he knows by the efficacy of the doctrine upon his heart, and the influence it has on his life and conversation; by its coming not in word only, but in power; and by its working effectually in him, whether it is divine or human, of God or of man.