John Lightfoot on Luke 5:1

[To hear the word of God, he stood by the lake, &c.] For they were wont to teach also without the synagogue and Beth Midrash, in the highways and in the streets. "Rabban Jochanan Ben Zaccai taught in the street before the Mountain of the Temple the whole day." See the Gloss upon it: "Ben Azzai taught in the streets of Tiberias."

This custom R. Judah forbade in this canon: "Let not the doctors teach their disciples in the streets." And accordingly he severely rebuked R. Chaijam, because he taught his brothers' sons in the street.

And yet it is related of the same R. Judah, R. Judah sat labouring in the law [labouring in the word and doctrine, as the expression is 1 Timothy 5:17], "before the Babylonish synagogue in Zippor: there was a bullock passed by him to the slaughter, and it lowed." This bullock because he did not deliver from the slaughter, he was struck with the toothache for the space of thirteen years.