Responsa zu Hoschea 4:25

Regarding biblical law, we follow the stringent position, as [the existence of multiple views is like having] a doubt concerning a biblical law. Regarding rab-binic law, we follow the lenient position, as is found in the first chapter of Avodah Zarah (7a). One who relies on the lenient position regarding biblical law, trans-gresses. He is among those about whom it is said “its stick directs it” (Hoshea 4:12), as we have said. However, if there is a rabbi in their place who has taught them, they follow his words. This is [seen in the case of] the difference between the land of Israel and the land of Bavel re-garding a certain fat on the innards –these prohibit eating it and those permit it. One may even eat it in secret in Bavel, if he plans on returning to be counted among the people of his place [Israel], even though it is a biblically forbidden fat according to those in Bavel.

In Rabbi Eliezer’s region, they would cut wood [on Shabbat] to make charcoal to make the knife [for circumcision], and the sages did not protest as they were acting like their teacher. And in the chapter Kol HaBasar (Chullin Chapter 8, 116a) it says, “Levi visited the town of Yosef Rishba. They served a head of fowl cooked in milk. He did not eat, and said nothing. When [Levi] returned to Rav, he said, “Why didn’t you excommunicate them?!” He replied, “That is the town of Rabbi Judah ben Beteira. I thought per-haps he expounds like Rabbi Yossi the Galilean’s opinion, who says ‘poultry meat is excluded [from the prohibition of meat and milk] for it does not produce milk.’” And so too in many cases. In a similar way, people who have accus-tomed themselves based on one of the great authorities, [such as] the places where they act in all their actions based on the laws of Rif z”l, and the places where they always act based on Ram-bam’s code -they have made these great ones their teachers. However, if there is a sage worthy of ruling, and he sees a proof to forbid what they permitted, he can forbid it, for this [deceased figure] is not actually their teacher, and if they were to act differently than their actual teacher in his place, it would be lessening the honor of their teacher in his place... In a place where there are two equal ones, they follow the strict one regarding biblical law, but only if it is one against one. However, it if is two against one, we follow the majority. And if a student worthy of issuing halachic rulings agrees with the posi-tion of the lenient one, perhaps they may follow his leniency because he agrees with the ruling of the lenient one and then it is majority against an individual.