Orthodox theology and plays a key role in understanding how God relates to the world. This distinction, whose roots can be traced back to Greek philosophy—particularly in the thought of Aristotle and the Neoplatonists—was first articulated in Christian theology by the Cappadocian Fathers and later became one of the cornerstones of Orthodox theology through the writings of Gregory Palamas. According to this doctrine, the divine essence is beyond the reach of creatures, yet God is present in the world through His uncreated energies, making possible human participation in them. This article examines the historical development of this concept from Aristotelian philosophy to Eastern Orthodox theology, analyzes its implications for grace, soteriology, and mysticism, and highlights its difference from Western theology. It also explores the impact of this doctrine on the understanding of divine presence, ecclesial structure, and religious experience in Eastern Christianity. The findings of this study indicate that the essence–energies distinction not only elucidates the fundamental theological differences between East and West, but also offers a new framework for understanding grace, salvation, and mystical experience, while opening avenues for comparative study with the distinction between divine essence and manifestations in Islamic mysticism.