For much of church history, theologians and exegetes have believed that the Apostle Paul was a member of the Jewish sect known as the Pharisees. And why wouldn't they? The New Testament states this very thing, does it not? In fact, Paul claims to have been a Pharisee (Phil. 3:5), doesn't he? However, the original Greek is much more complicated and may not actually mean what historians have traditionally thought.
World-renowned expert on ancient Near Eastern and biblical languages, Rabbi Dr. Charles David Isbell, who was also an original member of the translation committee for the New American Standard Bible, has recently suggested that Saul of Tarsus may not have, in fact, been a Pharisee afterall. Indeed, according to Dr. Isbell, the beliefs and characteristics of Paul's pre-conversion life indicate closer affinities with the Sadducees than they do with the Pharisees. Is it possible that Paul never really claimed he was a Pharisee in the first place and this his initial opposition to the Jesus movement was because of a Sadducean rejection of resurrection theology?
In his article, "Saul the Sadducee? A Rabbinical Thought Experiment," Dr. Isbell argues that there exists a striking disparity between Paul and other first century Pharisees, particularly since he took far too many liberties with his beliefs and behaviors (pre- and post-conversion) that would have set him apart from his Pharisaic contemporaries. In fact, Paul’s radical revision of prevailing Pharisaic exegesis suggests he was likely never a Pharisee or, at the very least, not a consistent Pharisee in the tradition of Gamaliel. Moreover, Luke (a non-Jew writing in a post-Sadducean world) was both an unreliable biographer and yet the primary source for claiming Paul was a Pharisee. Thus, from a Jewish perspective, it is thought-provoking to ask whether the idea of Paul as originally a Sadducee best explains these disparities.
You can read Dr. Isbell's entire article for free as part of the Global Center for Religious Research's commitment to continued exploration into uncharted and unique areas of study.