311
A.D.
Methodius of Olympus
Patristic
c. A.D. 260–311
“For we believe that, together with the Son, who was made man for our sakes, according to the good pleasure of His will, was also present the Father, who is inseparable from Him as to His divine nature, and also the Spirit, who is of one and the same essence with Him. For, as says Paul, the interpreter of the divine oracle, "God was in Christ reconciling the world unto Himself, not imputing their trespasses unto them." He thus shows that the Father was in the Son, because that one and the same will worked in them.”