The article is a theological investigation of the Grace-filled Flame based ob analysis of the Orthodox tradition authentic texts, including the Holy Scripture, Books of the Old and New Covenant, Holy Fathers' writings, sacred worship chants. In result of analysis the author comes to the conclusion that the very notion of the Grace-filled Flame being immutable in the course of its existence is the integral attribute of the Orthodox Church spiritual practice and theology. The problem is analyzed in terms of Grigory Palama’s theology. According the hypothesis set forth in the article the Grace-filled Flame is the portent of the Lord and a human being meeting and their spiritual and energetic mergence.