Oh, how perfect love is always ready for perfect obedience! After all, perfect love cannot be perfectly expressed in any other way than by perfect obedience.
Love is always vigilant in its desire and readiness to obey its beloved. And from perfect obedience flows, just like a stream of honey and milk, perfect joy, which is the content of the attractive power of love.
The Father has perfect love for the Son and the Spirit. The Son has perfect love for the Father and the Spirit. And the Spirit has perfect love for the Father and the Son.
According to this perfect love, the Father is in the most zealous obedience to the Son and the Spirit, and the Son is in the most zealous obedience to the Father and the Spirit; and the Spirit is in the most zealous obedience to the Father and the Son.
Perfect love makes the Father the perfect servant of the Son and the Spirit; and the Son, the perfect servant of the Father and the Spirit; and the Spirit, the perfect servant of the Father and the Son.
Just as no love in the created world can be compared to the mutual love of the Divine Hypostasis, neither also can any obedience be compared to Their mutual obedience.
I have glorified Thee on earth: I have finished the work which Thou gavest me to do (Jn. 17:4). May Thy will be done. Are these not the words of the Son’s perfect obedience to the Father?
Father, I thank Thee that Thou hast heard me. And I knew that Thou hearest me always, said the Lord Jesus Christ at the resurrection of Lazarus; and later He would exclaim: Father, glorify Thy name.
Then came there a voice from heaven, saying, I have both glorified it, and will glorify it again (Jn. 11:41–42; 12:28). Is this not the perfect obedience of the Father to the Son?
Nevertheless I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you (Jn. 16:7).
And I will pray the Father, and he shall give you another Comforter, that he may abide with you forever… But when the Comforter is come, whom I will send unto you from the Father, even the Spirit of truth, which proceedeth from the Father, he shall testify of me (Jn. 14:16; 15:26).
And truly, on the fiftieth day after the Resurrection, the Comforter, Spirit of Truth descended upon those to whom it was promised. Is this not the perfect obedience of the Holy Spirit to the Son?
Nikolai Velimirovich (1880-1956; Orthodox Church): The Day of the Holy Trinity. Pentecost: The Gospel of the Descent of the Holy Spirit @ Pravoslavie.