When responding to the accusations brought against Hesychasm by Barlaam, a monk of Calabria, Gregory Palamas, the Greek Saint (1296-1359), of the Eastern Orthodox Church, a Monk of Mount Athos, a theologian of Hesychasm and the Archbishop of Thessalonica, made reference to the teachings of the Cappadocian Fathers – Basil the Great, Gregory of Nazianzus and Gregory of Nyssa, as well as to the thoughts of Dionysius the Areopagite or Symeon the New Theologian. Also, he drew a distinction between the unknowable essence (nature) of God ousia, and the energies emanating from Him –energeiai – which should be distinguished from ousia, His Essence.
He calls those gifts a mysterious deification (theose) present as emanations expressed in the gifts of the Holy Spirit referring to the words of The Letter to the Hebrews: „God himself confirmed their witness with signs and marvels and miracles of all kinds, and by freely giving of the Holy Spirit” (Heb 2:4). The gifts exist as God’s external actions energeiai responsible for the deification of the man.