Fr. Georges Florovsky 1893-1979
[T]he distinction between “grace” and “essence”: he theia kai theopoios ellampsis kai charis ouk ousia, all’ energeia esti Theou [the Divine and Divinizing illumination and grace is not the essence, but the energy of God; St. Gregory Palamas Capita Phys., Theol., etc., 68-9]. This basic distinction was formally accepted and elaborated at the Great Councils in Constantinople, 1341 and 1351. Those who would deny this distinction were anathematized and excommunicated. The anathematisms of the council of 1351 were included in the Rite for the Sunday of Orthodoxy in the Triodion. Orthodox theologians are bound by this decision. (St. Gregory Palamas and the Tradition of the Fathers)