"Thus shall ye do in the fear of the Lord, faithfully, and with a perfect heart ... Deal courageously, and the Lord shall be with the good" (2 Chronicles 19:9-11)
Now how does that power operate? At its purest it is an unmediated force directly applied by the Spirit of God to the spirit of man.
The wrestler achieves his ends by the pressure of his physical body upon the body of his opponent; the teacher by the pressure of ideas upon the mind of the student; the moralist by the pressure of duty upon the conscience of the disciple. So the Holy Spirit performs His blessed work by direct contact with the human spirit.
The Spirit of God may use a song, a sermon, a good deed, a text or the mystery and majesty of nature, but always the final work will be done by the pressure of the indwelling Spirit upon the human heart.
The Spirit's first work is to cleanse us, to separate us, to sanctify us, to dedicate us wholly to God. Then as the property of God, He takes possession of us for God and uses us for His service and glory alone.
~A. W. Tozer~