R. Ze’ev Nahum Borenstein was av bet din in Biala. His son, R. Abraham ben Ze’ev Nahum of Sachaczew (1839–1910) was head of the bet din of Sochaczew. He became famous as a child prodigy. At the age of 14 he married the daughter of R. Menahem Mendel of Kotsk, in whose home he remained for ten years studying Torah and Hasidism. Upon his father-in-law's death, he occupied rabbinical posts in Parczew (1862), Krosniewice (1866), Nasielsk (1876), and Sochaczew (1883–1910). In 1870, following the death of R. Hanokh Henyekh, leader of the Aleksandrow Hasidim, he was appointed his successor, but was harassed by slanderers. Abraham founded a yeshivah and was one of the great halakhic authorities of his generation. He originated a special approach to halakhic studies and educated in his yeshivah a generation of disciples who became scholarly hasidic leaders. Interested in the settlement of Erez Israel, he sent his son and son-in-law there in 1898 to acquire land for a religious colony, but negotiations fell through on account of the Turkish land laws. R. Abraham's halakhic works are Eglei Tal (1905), including a study of the laws of the Sabbath, and Avnei Nezer (1912–34), a collection of responsa on the four parts of the Shulhan Arukh. He was succeeded as head of the Aleksandrow Hasidim by his only son, R. Samuel (1856–1926), who edited his father's writings and responsa on the Shulhan Arukh, and wrote Shem mi-Shemu'el (1928–34) which sets forth many of his father's ideas on Hasidism.

הסכמת בן המחבר: ר' אברהם [בארנשטיין], מסאכטשאב, אטוואצק, מוצאי שבת ואתחנן תרס"ד. - חלק א עם הסכמת בן המחבר והקדמת חתן המחבר, ר' יעקב אורנר, שבאו בחלק א. - חלק ב

חלק א: מן אות א עד אות ע (איסור כולל-סימנין). ווארשא, דפוס דובערוש טורש, תרס"ו, 1904 [!]. [2], 258 עמ'. חלק ב: מן אות ע עד אות ת (עד אחד נאמן באיסורין - תקנות עגונות). בילגורייא, דפוס נתן נטע קראנענבערג, תרס"ט. 232 עמ'.