The Hebrew word in the Old Testament, employed to designate the Holy Spirit of God, the third Person of the Holy Trinity, is ruach, signifying wind or spirit. The corresponding word in the New Testament is pneuma, likewise signifying wind or spirit.
When God chose to reveal Himself to mankind, He inspired men to commit His communications to writing. There is always a difficulty, in using the vehicle of human language, of giving full expression to Divine thoughts. Human language is designed to meet the needs and thoughts of men, and is bounded by time and sense. Divine thoughts, on the other hand, take a range far beyond the spheres of time and sense. To meet this difficulty the Spirit of God has often stamped words, familiar to man in his ordinary speech, with a new and higher meaning. This was so with the words mach (wind, spirit) and pneuma (wind, spirit). Quite plainly these words are often used in Scripture to designate a Person-the Holy Spirit of God. There is no difficulty in recognizing this in the Scriptures.
There is one particular passage of Scripture that shows how the ordinary word pneuma (wind, spirit) is used as a simile of the Spirit of God. We read our Lord's own words: " The wind [pneuma] bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit [pneuma] (John 3:88The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit. (John 3:8)).
I remember a very intelligent child asking his mother how could anyone know that he had a spirit, seeing it is invisible? The mother replied, " Mr. Pollock is coming to tea to-day. When he comes, we will ask him." In due time the question was propounded. The spirit in man cannot be seen or weighed or located. It is said to be in our body. How can we know this? I said to the boy, " Have you ever seen the wind?" He answered, " No." I then asked, " Can you feel the wind?" He answered, " Yes." I replied, " That is like the spirit. Without our spirit we should be dead. The Bible says, The body without the spirit is dead.' You are not dead. That proves that you have a spirit." This answer quite satisfied the boy. It was his first introduction to the thought that existence can be apart from that which is material. The simile of the wind proved most useful. How apt the simile used by our Lord when He spoke to Nicodemus of the necessity of the new birth.