IDI B. JACOB II:
Babylonian amora of the second period (about 250). Idi was a disciple of Johanan. The journey from Idi's home in Babylonia to the yeshibah of Johanan at Tiberias occupied about three months, and two journeys there and back in the year left him but one day each six months to attend the yeshibah. This caused his comrades to call him "the one-day scholar." Idi answered by quoting Job xii. 4. Johanan, however, begged Idi not to call down the punishment of Heaven, and delivered a lecture in the yeshibah on the text "They seek me daily" (; Isa. lviii. 2), concluding with the statement that to devote a single day to learning the laws of God is as meritorious as devoting a whole year to study. On the other hand, one day spent in doing evil is equivalent to one year of iniquity; which explains the imposition of forty years of punishment for forty days of evil (Num. xiv. 34; Ḥag. 5b). Idi was likewise known as Idi of Ḥuṭra, (Yer. Shab. v., end; M. Ḳ. v. 2), and is probably identical with Idi of Cæsarea (Idit).