John 7:17 “If any man will do his will, he shall know of the doctrine, whether it be of God, or whether I speak of myself.”
If any man will do God’s will, He shall know the truth. Jesus is telling them here, that just knowing the letter of the law is not enough; they must know the Giver of the law. They must be willing for God’s will to be done in their lives.
You could memorize every word in the Bible; but it would do you no good, unless you allowed God to open your understanding to His Word. Jesus says “If you are truly in right standing with God and His Word, then you know that I am of God.”
You see, the entire Bible is all about Jesus Christ. He is the theme of the Old Testament and the New Testament.
Those who are fundamentally committed to doing the will of God will be guided by Him in the affirmation of His truth. God’s truth is self-authenticating through the teaching ministry of the Holy Spirit.
In short, if you are not filled with the Holy Spirit and are led and guided by Him, you are not a Christian.