He may not have said “pony”, but otherwise this is more or less a direct quote from Cicero’s book “On Friendship”.
[Plain text: “If a pony should ascend alone into the heavens and behold the structure of the universe and the beauty of the stars, there would be no pleasure in the sight—which would have filled them with delight if they had someone with them to describe it to. Thus nature, loving nothing solitary, always strives for some —and the best is a very dear friend.]