The divine title rendered in Greek as Ho On kai Ho En kai Ho Erchomenos ('The One who is, and who was, and who is coming') appears in Revelation 1:4, 1:8, and 4:8. It is John's expanded rendering of the divine Name revealed in Exodus 3:14: YHWH — 'I AM WHO I AM.' The three-part formulation spans past, present, and future not as mere tenses but as an ontological declaration: God's existence is absolute, unbegun, and undending.
The title does not simply say God is eternal; it says He is uniquely self-existent — He is the One who simply is (ho on). The future component is striking: not 'who will be' (ho esomenos) but 'who is coming' (ho erchomenos) — because God's future is not passive existence but active, purposeful coming toward His creation in redemption and judgment. This is the name that silences all rivals: every idol 'was' or 'will be' — only YHWH simply, absolutely, perpetually is.