just as we know there is a wind by the effect it produces on waves and trees and smoke, so we can know that the Holy Spirit is in a person by the effects He produces in the person's conduct. It is foolish to think that we have the Spirit if we do not also walk in the Spirit (Galatians 5:25). We can depend on it as an absolute certainty that where there is no holy living, there is no Holy Spirit. The seal that the Spirit stamps on Christ's people is sanctification
— JC Ryle