It seems Roddenberry was preceded in this idea by Alice Meynell (1847-1922), an English Catholic mystical poet, who wrote the following marvellous poem in 1917.
Christ in the Universe
With this ambiguous earth
His dealings have been told us. These abide:
The signal to a maid, the human birth,
The lesson, and the young Man crucified.
But not a star of all
The innumerable host of stars has heard
How He administered this terrestrial ball.
Our race have kept their Lord’s entrusted Word.
Of His earth-visiting feet
None knows the secret, cherished, perilous,
The terrible, shamefast, frightened, whispered, sweet,
Heart-shattering secret of His way with us.
No planet knows that this
Our wayside planet, carrying land and wave,
Love and life multiplied, and pain and bliss,
Bears, as chief treasure, one forsaken grave.
Nor, in our little day,
May His devices with the heavens be guessed,
His pilgrimage to thread the Milky Way,
Or His bestowals there be manifest.
But, in the eternities,
Doubtless we shall compare together, hear
A million alien Gospels, in what guise
He trod the Pleiades, the Lyre, the Bear.
O be prepared, my soul!
To read the inconceivable, to scan
The million forms of God those stars unroll
When, in our turn, we show to them a Man.
What more can I add but that I hope to meet Alice Meynell in Sto-Vo-Kor!
(BTW if you follow the above link, I disagree with the encyclopedia's assessment of Sto-Vo-Kor as mythology).