SYMEON THE NEW THEOLOGIAN (949–1022)
The grace of the Holy Spirit does not come from the outside, but is within the heart, and it is the only true and divine source of knowledge…. If someone has truly received the Spirit, they will have knowledge of God, not by thinking about Him, but through living experience…. The true light is the light of the Holy Spirit, and when this light shines in the soul, the whole person becomes enlightened and knows God directly, not through words or ideas.