In the dialogue Meno, Plato explains that virtue is not a science, for if it were, there would be masters in the science, but there are not. He also says heroes in Greece, good in varied activities, and also virtuous, pursued the education of their sons in these activities, but in the field of virtue, they weren't capable to transmit it, as someone who transmits the arithmetic knowledge that two plus two equals four.
For Plato, then, virtue is not something the virtuous person has the possession of, but is a god gift. "If not due to science, then due to a happy opinion? Making use of it, politicians rule cities, not being in any degree differents, as to understanding, from inspired soothsayers or oracle pronouncers. For these too, when gods are in them, speak the truth, even about a lot of things, but don't know about the things they say." This theme will be treated again by Plato in the Apology of Socrates, when he pictures Socrates as the wisest man in Greece, even if he is not fully conscious of that, compared to other characters of greek life, specially ones from the poetical genre, which are capable of telling great stories with extremely beautiful words, but hardly know how they did it; while he, Socrates, knew he was ignorant in several matters others had the conviction, wrong one, they were masters of. Of course the common belief Socrates was a silly man afters answers is not proper, for he showed himself extremely ironical and soaring talking. He kept, nonetheless, a deep respect for the mistery of life.
The philosopher from the Academy finishes up the matter in the following manner: "But if us, in all this discussion, have researched and discussed to the point, virtue wouldn't be by nature something to be taught, but a god concession, which comes without understanding to the one it comes." This phrase throws to the ground any researcher who ever thought of calling him a gnostic. Here he explicitly asserts virtue does not derive from knowledge, for if it did, it could be taught, being though a god gift. Centuries lates Jesus would prefer among his apostles the common men, including two that could be called mediocre. Jesus did not repudiate intelligence, on the contrary, but he also did not despise the ones who didn't have it.
In the Urantia Book, it is told Jesus "taught morality, not from the nature of man, but from the relation of man to God." That means, the solipsist man can't be good, for man needs a personal relation with God. "Jesus' morality was always positive. The golden rule as restated by Jesus demands active social contact; the older negative rule could be obeyed in isolation."