1 John Chapter 5
It is an amazing thing that in a comparatively small book such as First John the word "know" is used twenty-five times, and in the fifth chapter, which we are presently considering, it is mentioned seven times. We are constantly meeting those who challenge our ability to know that we are saved (v. 13); to know that we have the truth (v.20); and to know that our prayers are answered (v. 15). It will be evident that John has no doubts concerning our ability to be confidently certain of the reality of all of these things.
Christianity is not a speculative religion except for those who know nothing of the indwelling of the Holy Spirit. An unregenerate man, however brilliantly trained, can approach the Scriptures with as shrewd a literary analysis as applied to Plato's Republic, or Shakespeare, and will find nothing whatever within the Word to give him the assurance that the believer finds therein. The Scriptures teach us (1 Cor. 2:14) that "The natural man receiveth not the things of the Spirit of God; for they are foolishness unto him: neither can he know them, because they are spiritually discerned." The prerequisite, as we have already learned (1 Jn. 2:20), to genuine knowledge of truth is the unction of the Holy Spirit. For this reason an unregenerate criticism of the Scriptures is, for the believer, totally meaningless. Ephesians 2:1 makes it adequately clear that the natural and unregenerate man is of himself spiritually inert. Only the quickening power of the Holy Spirit can awaken his soul to the truth of God and to the confession that Jesus Christ is Lord. Scripture declares, "...no man can say that Jesus is the Lord but by the Holy Spirit" (1 Cor. 12:3).
The world will continually refuse our testimony on this matter and refuse to recognize that there is a supernatural impartation to every genuine believer in Christ. We must not blame them for there was a time when we too could not see until the Holy Spirit quickened us.
(by Dr. Robert M. McMillan)