God alone is the being, the unique and genuine reality. Consequently union with God is the only guarantee of a complete personal being. Separation from God is equivalent to loss of claim to one's own existence. God is life: privation of life is death. Hence the sinner separated from God is in reality dead, though he continues to exist as far as the body is concerned. The unending existence in the state of damnation of his soul is rightly described not as everlasting life, but everlasting death.
Reference~ The Doctrine of Spiritual Perfection, Anselm Stolz