The Spirit helps us in our weakness. For we do not know what to pray for as we ought, but the Spirit Himself intercedes for us with groanings too deep for words. And He who searches hearts knows what is the mind of the Spirit because the Spirit intercedes for the saints according to...
But we must come down towards the year 360 to find the doctrine on the Holy Ghost explained both fully and clearly. It is St. Athanasius who does so in his "Letters to Serapion" (P.G., XXVI, col. 525 sq.).St. Basil, Didymus of Alexandria, St. Epiphanius, St. Gregory of Nazianz...