창세기 27:48의 Responsa

They answered:"Reason is not with the aged, and counsel is not with the young." (Shabbat 89b:4) "For Abraham knows us not, Israel does not recognise us" (Isaiah 63:16), rather "my covenant will be made with Isaac." (Genesis 17:21), "I have singled him out," (Isaiah 51:2) "and will give him the birthright," (Psalms 89:28) "and he shall be blessed." (Genesis 27:33)^*These verses seem to support Isaac, i.e, R. Isaac Alfasi, over the Abraham and Jacob, perhaps referring to Rabbeinu Tam.

They responded: "No hand shall touch it, for he shall be stoned." (Exodus 19:13), and they continued, "The voice is the voice of Jacob and the hands are the hands of Esau," (Genesis 27:22) and it is therefore clear that it is forbidden to go out wearing them.

They responded: "How quickly have you found your desire, my son," (Genesis 27:20) "Shining ['Zarach'] in the darkness is light for the upright ['Yesharim']." (Psalms 112:4) ^*Possibly, the meaning here is that R. Zerachia is in the darkness, while Rashi (the letters of his name are in the word Yesharim) is in the light and should be followed. Another possibility is that the first verse, spoken by the biblical Isaac, is a reference either to Rashi (R. Shlomo Yitzhaki) or to the Rif, R. Isaac Alfasi, who omits the statements of Rabbi Zeira in his Talmudic commentary. See Keset Hasofer ad loc. It is also unclear here to what extent the question here is theoretical. Maimonides omits the calendrical calculations as a commandment, while Sefer Mitzvot Gadol 47 seems to hold that it is a positive commandment incumbent upon every Jew who is able to make such calculations.