רבי אליעזר ברבי יוסי

Rabbi Eliezer ben Yose was a tanna whose teachings appear in the Mishnah and Gemara on matters of practical halachah. In tractate Megillah he is recorded debating the proper time for reading the Megillah and the related gifts to the poor; the Gemara presents his view alongside that of Rabban Shimon ben Gamliel and frames the dispute around a single verse that both expound. Rabbi Yochanan explains that Rabbi Eliezer holds the reading in a leap year should fall in the Adar adjoining Shevat — the first Adar — and his reasoning is grounded in the principle that one does not pass over a mitzvah when it presents itself.

In tractate Eruvin he addresses the measurement of the Levite cities’ boundaries, teaching that of the two thousand amos of the open lands, one thousand amos serve as the migrash (open space) and the remainder is given over to fields and vineyards. These passages show him engaged in careful definition of measures and timings in halachah.