The answer is: Resurrection

Mark 12:18

The Sadducees were quite a unique bunch during the time of Jesus, embodying a powerful priestly class within Jewish society. Unlike other groups like the Pharisees, they didn't accept the oral traditions or interpretations of the Torah; they stuck to the Official Law of Moses – plain and simple. That rival interpretation set the stage for many crispy debates in the Gospel.

One of their most notable beliefs was the denial of the resurrection of the dead, as Mark 12:18 indicates. This principle gave them a foothold in the earthly privileges of power and wealth since if there's no afterlife, everything is about the here and now. Imagine the Sadducean leaders uppercrusting their way through the tunes of the temple choir while dismissing conversations about life beyond this one!

An interesting tidbit? The word “Sadducees” is thought to derive from “Zadok,” a high priest in King David's time, underscoring their scribal authority—like a sort of ancient heir to temple royalty.

While the Sadducees might cast shadows on the notion of resurrection, their counterpart, the Pharisees, held strong beliefs about what lay beyond this world. It created a fascinating theological tug-of-war during Jesus' ministry, challenged by glass ceilings, if you'll indulge the term, on both sides of the afterlife debate! This adds rich layers to the conversations Jesus had with groups within Judaism, contributing to the struggle and shaping of religious discourse then and now.