In the context of Evangelical reformulations of the Trinity in a new sub-ordinationism, the article reasserts the traditional assertion of the full equality of all persons of the Trinity. To that end, the author exposits John Calvin’s formulation of the Trinity and that of the church fathers, which anticipates Calvin’s doctrine. Crucial to a proper understanding are the distinctions between essence and persons and between the ontological Trinity and each person’s role in redemption. The historical survey concludes with B. B. Warfield’s and Thomas F. Torrance’s assessments of Calvin’s contribution. Finally, three implications linked to our doctrine of God—knowledge, forgiveness, and love—are considered.