 He made light, too, of the decisions of his contemporaries, and thus drew on himself the enmity of some among them, including David ben Shmuel HaLevi, author of "Ture Zahav", and Aaron Shmuel Kaidanover, author of "Birkhat HaZevach", who was the father-in-law of his brother Yonah Menachem Nachum HaKohen.Nevertheless, "Sifsei/Siftei/Sifte Kohen", Shakh's commentary on the "Shulchan Aruch", was considered by a majority of Talmudists as of the highest authority, and they applied his decisions to actual cases as the final word of the Law.As a logician he stood, perhaps, first among the Talmudic scholars of his age.