The work of the Holy Spirit, though mysterious, will always be known by the fruits He produces in the character and conduct of those in whom He dwells. The presence of the Spirit is like light which can be seen, fire which can be felt, and wind which causes noticeable results.
Where there are no fruits of the Spirit, there is no presence of the Spirit. Those fruits are always the same: conviction of sin, true repentance, living faith in Christ, and holiness of heart and life.
I am afraid there are multitudes of professing Christians throughout the land who really know nothing about the Holy Spirit. They seem to think that as baptized members of a church denomination, they possess the Spirit. But of the work of the Spirit on their own individual hearts–conversion, repentance, and faith–they know nothing at all. They are spiritually asleep and dead, and unless they awake, they are in great danger!
– J. C. Ryle