The Sensitivity of the Holy Spirit

We don’t hear much anymore about what it means to grieve and quench the Holy Spirit. As a result, many Christians have a weakened sense of direction and discernment. The Holy Spirit is the most sensitive person in a believer’s life. When we’re not sensitive to Him, we grow insensitive to sin. So what’s the difference between grieving and quenching the Holy Spirit; and how do you know when you’re doing it?