While revival originates from God, the Holy Spirit has appointed certain means to be used for the advancement of His kingdom. The foremost of these is the preaching of the Word of God accompanied by earnest prayer. Yet, no amount of human endeavor can assure results. The same is true of revival: no measured amount of our activity will guarantee an equivalent blessing, for God's blessing is bestowed according to His good pleasure (Zech. 4:6).
John Sale