Rav Naḥman bar Yitzḥak said: Nowadays the universally accepted practice is in accordance with the views of the following three Elders:
That of Rabbi Ilai with regard to the first sheared wool, for it has been taught: Rabbi Ilai says: The law of the first sheared wool applies only in the Land of Israel;
That of Rabbi Yoshiya with regard to kilayim – diverse kinds – for it has been taught: Rabbi Yoshiya says: A man is not liable for the infringement of this law until he sows wheat, barley and a grape pit with one throw of the hand.
The commentaries note that Rav Naḥman bar Yitzḥak’s teaching is significant because the majority of Sages disagreed with each of these three opinions. For example, according to the Gemara in Berakhot (daf 22a) most of the tanna’im and amora’im agree that someone who had a seminal emission and was rendered ritually unclean may not study Torah until he immerses in a mikveh. Nevertheless, as Rav Naḥman bar Yitzḥak attests, accepted practice was to follow these more lenient opinions, which is the accepted ruling today.
The law forbidding someone who was unclean because of a seminal emission to study Torah was established by Ezra during the Second Temple period. One question raised by the aḥaronim is how Rav Naḥman bar Yitzḥak could reject a longstanding tradition, when such power is only given to a court that is greater than its predecessor, which was not the case here. Among the explanations was that an enactment that was never fully accepted can be rejected by a later court. Others suggest that Ezra’s original enactment was based on its being accepted by later courts, as well.