《太平广记·卷十·神仙十》
我这两卷注解道经的著作，写了已经一千七百多年了，只传了三个人，算上你才四个人，希望千万不要把它给不相干的人看！ 
公乃授素书二卷与帝曰： 熟研之，此经所疑皆了，不事多四矣，勿以示非其人。 
These two scrolls I used to annotate the Daoist scripture, written over a thousand and seven hundred years ago, have only been passed on to three people, so with you there will only be four. Please make sure that you do not show them to anyone who is not suitable to have them! 