This paper proposes a Pentecostal-Palamite Trinitarian ontology of Christian religious experience, based on Pentecostal and Hesychast expressions of their experience of the Trinity's revelation and re-velation in creation. Grounded in the conviction that theology must be drawn from religious experience, it argues that not only it is at the core of both traditions, but, since they share the same experiential reality—the Trinitarian God—an integrated approach to them can produce an ecumenical Trinitarian ontology. The first section traces the history to the thirteenth and fourteenth centuries, to what Vladimir Lossky has termed the 'pneumatological colouring' of Byzantine theology. It seeks to identify the Trinitarian dimension of the Hesychast religious experience present in the Jesus Prayer—"Lord Jesus Christ, Son of God, have mercy on me"—which forms part of the Hesychasts' method toward deification. The second section focuses on the Trinitarian dimensions of Pentecostal experience, specifically by exploring religious expressions in worship lyrics. Finally, taking St. Gregory Palamas' ontological theology of divine energies as a framework to interpret the religious expressions pointed out in the previous sections, a Pentecostal-Palamite Trinitarian ontology will be developed: it is through the divine energies that we experience God in creation. The Trinity's divine energies are named, drawing from the Christian encounter with God. The focus of this section will be, first, to understand how the whole Trinity is at work on the Eternal Light, which is one of the divine energies experienced by the Hesychasts. Second, from the Pentecostal side, to describe Pentecost as an energy of the Spirit, the Father's energy of paternity, and Jesus Christ's energy as Man and Son of God, as Child, Lord and Bringer of the Kingdom. Additionally, it will be clarified how each one of these energies is of the whole Trinity, although the Persons have particular roles in each of these.