The Holy Spirit A B Simpson Chapter 14 – The Holy Spirit in Galatians Here is God’s great secret of holiness; not fighting sin, but being filled with God. It is the old principle of the expulsive power of a stronger force and a supreme affection. Just as water excludes air from that tumbler when it is filled with water; just as light excludes the darkness when the room is lighted, so the indwelling of the Holy Ghost excludes the presence and power of sin.