Bavli Ḥagigah

The words of the wise are as goads, and as nails well fastened are those that are composed in collections; they are given from one shepherd (Ecclesiastes 12:11).

Why are matters of Torah compared to a goad? To tell you [that] just as this goad directs the cow to her furrow to bring forth [sustenance for] life to the world, so too the words of Torah direct those who study them from the paths of death to the paths of life. If so, [should you think that—Ed.] just as this goad is movable, so too matters of Torah are movable, the verse states: Nails. If so, [should you think that—Ed.] just as this nail is diminished [in size] and does not expand, so too matters of Torah are diminished and do not expand, the verse states: Well fastened [netu‘im]. Just as this plant [neti‘a] flourishes and multiplies, so too matters of Torah flourish and multiply.

Those that are composed in collections [ba‘alei ’asufot]: These are Torah scholars who sit in many groups [’asupot] and engage in Torah [study. Some of] these [sages] render [an object or person] ritually impure and these render it pure; these prohibit [an action] and these permit [it]; these deem [an item] invalid and these deem it valid.

Lest a person say: Now, how can I study Torah [when it contains so many different opinions]? The verse states: They are all given from one shepherd (Ecclesiastes 12:11). One God gave them; one leader, [i.e., Moses,] said them from the mouth of the Master of all creation, as it is written: And God spoke all these words (Exodus 20:1).

So too, you make your ears like a funnel and acquire for yourself an understanding heart to hear the statements of [those] who render [objects] ritually impure and the statements of [those] who render [them] pure; the statements of [those] who prohibit [actions] and the statements of [those] who permit [them]; the statements of [those] who deem [items] invalid and the statements of [those] who deem [them] valid.