In the second (1967) and succeeding Urantia Foundation printings, "are" was changed to "is." The original would seem to be correct because the plural verb is commonly used when "none" is the subject. (See Webster's; OED)
P1677:1, 149:6.12 "Well did the Prophet Jeremiah describe many mortals when he said: `You are near God in the mouth but far from him in the heart.' And have you not also read that direful warning of the prophet who said: `The priests thereof teach for hire, and the prophets thereof divine for money. At the same time they profess piety and proclaim that the Lord is with them.' Have you not been well warned against those who `speak peace to their neighbors when mischief is in their hearts,' those who `flatter with the lips while the heart is given to double-dealing'? Of all the sorrows of a trusting man, none are so terrible as to be `wounded in the house of a trusted friend.'"