Who were the Pharisees?
The Pharisees were the bearers of the ancient tradition of Torah interpretation which had been brought from Babylonia by Ezra the Scribe and his associates when they came to Jerusalem to re-establish Jewish tradition in the community of Jews who had remained in Israel after the destruction of the Temple by the Babylonians. The Judeans who had remained in the Land of Israel at the time that the elite of Judah were exiled from Jerusalem, had not had the intellectual religious leadership which had been the possession of those Jews who had gone into exile and kept the Torah and its traditions alive.
According to the accounts in the Books of Ezra and Nehemiah, heroic measures were adopted to reorganize the Jewish communities in the land of Israel and to institute the changes which led to the foundation of schools where the tradition of Torah interpretation could continue and develop. The men called Sofrim, the Scribes, were actually the scholars, those who studied the sacred books of biblical interpretation as well as those who copied them, the leaders of the renaissance which occurred in Israel after the foundations were set in place by Ezra,Nehemiah, and their associates.
The bearers of the tradition, who may not yet have been known as Pharisees, but clearly were of the traditional group that eventually were included in the movement that is known by that name, were the Hasidim, the Pietists who joined the Hasmoneans in their rebellion against the Hellenizers who were in control of the Temple, as well as the people who followed Judah Maccabee in his struggle against the priests who held Jerusalem at the beginning of the revolt. The majority of the People of Israel who were appalled, angered and shamed at the introduction of Pagan furnishings and rituals into the Temple in Jerusalem allied themselves to the Maccabees, the Hasidim, and the other Jews who preferred the teachings of the traditions.
All branches of Judaism throughout the ages, whether centered on the ancient tradition or considered deviant and sectarian, base themselves on the teachings of the Sacred Scriptures; the Torah, the Prophets and the other Holy Writings, which include the Psalms, the Proverbs and the other books. The sectarian divisions begin with interpretation of these sacred writings. Thus, in their disputations, each of the opposing groups will quote the Biblical writings to support its interpretation of its true meaning. So, in their arguments, the Sadducees and the Pharisees relied on their quotations from the Torah and the Prophets to prove their contentions and to disprove those who opposed them.