This is how Socrates came to be considered an almost proto-Jesus (for better or worse). It's an idea not much in vogue anymore, but Whitehead's observation is as true in this century as it was in the last.
The speaker is Alcibiades:
But when we listen to [Socrates], or to someone else repeating what [Socrates has] said, even if he puts it ever so badly....we're absolutely staggered and bewitched....Yes, I've heard Pericles and all the other great orators, and very eloquent I thought they were, but they never....turned my whole soul upside down and left me feeling as if I were the lowest of the low. But this latter-day Marsyas, here, has often left me in such a state of mind that I've felt I simply couldn't go on living the way I did....He makes me admit that while I'm spending my time on politics [!] I am neglecting the things that are crying for attention in myself. So I just refuse to listen to him....I've been bitten by something much more poisonous than a snake; in fact, mine is the most painful kind of bite there is. I've been bitten in the heart, or the mind, or whatever you like to call it, by Socrates' philosophy....He talks about pack asses and blacksmiths and shoemakers and tanners, and he always seems to be saying the same old thing in just the same old way.....But if you open up his arguments, and really get into the skin of them, you'll find that....nobody else's are so godlike, so rich in images of virtue, or so...entirely pertinent to those inquiries that help the seeker on his way to the goal of true nobility.
--Symposium, 215d-216a, 218a, 221c-222a
One note: a common complaint against the gospels is that they weren't written by Jesus, perhaps not even by people who knew Jesus. We are sure Plato knew Socrates; we're also just as sure there is an "historical" Socrates somewhere in some of the dialogues, and in others (such as The Republic), Socrates is merely Plato's sock puppet (to use the modern idiom). And yet, Whitehead is right: all of Western philosophy is just a footnote to Plato; and all of Western philosophy undergirds what we think is valuable, right, good, proper, worthwhile, noble, execrable, etc., etc. To escape it is to try to escape one's own skin; you simply can't do it. And yet no one complains about the veracity of Plato's dialogues.
Probably because so much emphasis is placed on the historicity of Jesus of Nazareth, and on whether the Jesus in the gospels is the Jesus who lived in first century Palestine. But to focus on that is to ignore what the gospels tell us Jesus said. Perhaps those reports are no more reliable than Plato's reports about Socrates; however, does that mean we can dismiss what Socrates says? Which matters more: who said it, or what was said?
Surely, in this post-enlightment era, the appeal to authority is dead. And after all, even if you don't admit the deity of the speaker, does that mean the arguments presented in his words are not "entirely pertinent to those inquiries that help the seeker on his, or her, way to the goal of true nobility? At least?