The only thing that saves us.
We can only keep ourselves in the love of God by building up ourselves on our most holy faith and by Holy Spirit praying, and by nothing else. If we try to fight God’s battles in our own moral, resisting power, we shall fail, and fail miserably, but if we use the spiritual weapons of implicitly trusting God and maintaining a simple relationship to Jesus Christ by praying in the Holy Spirit, we shall never fail.
Oswald Chambers
The Holy Spirit and Prayer
Paul more than once reminds his convert that the chief characteristic of his preaching was the supernatural power of the Holy Spirit.
There is no manifestation of the Holy Spirit when both the speaking (from the pastor) and the hearing (from the parishioner) are both mainly the working of human understanding and feeling.
Andrew Murray