Rabbi Yaakov Tzvi Mecklenburg—the HaKtav VeHaKabbalah רבי יעקב צבי מקלנבורג — הכתב והקבלה

He was born in 1785 at Lissa; he studied under Rabbi Akiva Eiger and long lived as a merchant, like many scholars of the Poznan region. In 1831 he became rabbi of Königsberg in East Prussia and led the community until his death—more than thirty years, in a city where the university and the Haskalah were near at hand.

His book is the HaKtav VeHaKabbalah, "The Writing and the Tradition", published at Leipzig in 1839: a commentary on the Pentateuch in which every halakhic tradition of the sages is traced back to the exact sense of the words of the verse—to the root, the grammar, the shade of meaning. So he answered those who said that the Oral Torah had grown onto the Written later and from outside: no, it is within it. The book stands with the Malbim and the Netziv as one of the three great commentaries of the nineteenth century written to that end.

He died at Königsberg in 1865.