A.D. 380
“No sooner do I conceive of the One than I am illumined by the Splendour of the Three; no sooner do I distinguish Them than I am carried back to the One.”
Oration 40 (On Holy Baptism), §41
Source
Source · a work in the library
Select Orations of Gregory Nazianzen
NPNF2 Vol. 7 (Browne & Swallow)
Public domain