Midrasch zu Mischlej 3:5

(Fol. 147b) R. Chelbo said: "The wine of the land Perugitha and the baths of the Lake of Dimsith ruined the ten tribes of Israel." R. Elazar b. Arach once happened to be there, and he indulged in those luxuries to such an extent that he forgot his learning and upon his return, he wanted to read the verse (Ex. 12, 2.) Hachodesh Haze Lachem (this month shall be unto you), instead of which, he read Hacharash Haya Libam (deaf were their hearts). The Rabbis prayed for his return unto the Torah, and so it was. This is meant when we are taught that R. Nehorai said: "Go into exile only in a place of Torah; say not that the Torah will follow thee, or that thy colleagues will preserve it for thee. And do not depend upon thine own acquired knowledge." It is taught that his real name was not R. Nehorai but R. Nechemia, and according to others, R. Elazar b. Arach, and the reason he was called Nehorai is because he enlightened the eyes of the sages with [his methods of explaining] the Halacha.