Mishnayot on Sources of the Law

m. Avot 5:22

Ben Bag Bag said: Turn it over, and turn it over again, for all is contained in it. And look into it, and become gray and old in it. And do not move away from it, for you have no better portion than it.

m. Rosh Hashanah 2:1–2, 5

1. If they don’t know him [the one who came to testify to the court regarding the new moon in order to determine the calendar], they send another with him to testify concerning [his reliability]. Originally, testimony concerning the new moon was accepted from anyone. When the minim [heretics] disrupted this, it was enacted [by a takanah] that testimony should be received only from persons known [to the court].

2. Originally, they used to light bonfires [to signal that the new month had been decreed]. When the Samaritans disrupted this [by lighting bonfires at erroneous times], they decreed that messengers would go out [instead]. [ . . . ]

5. There was a large courtyard in Jerusalem, and it was called Beth Yazek. All the witnesses used to assemble there, and there the court would examine them. And they would make large feasts for them there so that they would make it a habit to come. Originally, they would not move from there the whole day, but Rabban Gamaliel the Elder enacted [by takanah] that they could go two thousand cubits [outside the city] in any direction. And these were not the only ones [who could go two thousand cubits in any direction], but also a midwife who has come to deliver a child, or one who comes to rescue from a fire or from bandits or from a river or from a collapsed building. All these are like residents of the town and may go two thousand cubits [on the Sabbath] in any direction.

m. Shabbat 1:4

And these are among the halakhot that they stated in the upper chamber of Ḥananiah ben Ḥezekiah ben Gurion, when they went up to visit him. They voted, and Beth Shammai outnumbered Beth Hillel. They decreed eighteen matters on that day.