Albert Barnes Commentary John 7:17

"If any man willeth to do his will, he shall know of the teaching, whether it is of God, or [whether] I speak from myself." — John 7:17 (ASV)

If any man will do his will. Literally, if anyone wills or is willing to do the will of God. If there is a disposition in anyone to do that will, even if he is not able perfectly to keep His commandments. To do the will of God is to obey His commandments, to yield our hearts and lives to His requirements. A disposition to do His will is a readiness to yield our intellects, our feelings, and all that we have entirely to Him, to be governed according to His pleasure.

He shall know. He will have evidence, in the very attempt to do the will of God, of the truth of the doctrine. This evidence is internal, and to the individual it is satisfactory and conclusive. It is of two kinds.

1. He will find that the doctrines which Jesus taught commend themselves to his reason and conscience, and are consistent with all that we know of the perfections of God. His doctrines commend themselves to us as suited to make us pure and happy, and of course, they must be from God.
2. An honest desire to obey God will lead a person to embrace the great doctrines of the Bible. He will find that his heart is depraved and inclined to evil, and he will see and feel the truth of the doctrine of depravity; he will find that he is a sinner and needs to be born again; he will learn his own weakness, and see his need of a Saviour, of an atonement, and of pardoning mercy; he will feel that he is polluted, and needs the purifying influence of the Holy Spirit. Thus we may learn:
   1. That an honest effort to obey God is the easiest way to become acquainted with the doctrines of the Bible.
   2. Those who make such an effort will not dispute any of the doctrines of the Scriptures.
   3. This is evidence of the truth of revelation that everyone can apply to their own situation.
   4. It is evidence that leads to certainty. No one who has ever made an honest effort to live a pious life, and to do all the will of God, has ever had any doubt of the truth of the Saviour's doctrines, or any doubt that His religion is true and is suited to human nature. Only those who wish to live in sin doubt the truth of religion.
   5. We see the goodness of God in giving us evidence of His truth that may be within everyone's reach. It does not require great learning to be a Christian and to be convinced of the truth of the Bible. It requires an honest heart and a willingness to obey God.

Whether it be of God. Whether it is divine.

Or whether I speak of myself. Of myself, without being commissioned or directed by God.