The Sanhedrin, which was the Jewish senate, saw Jesus as a threat to their power and security. That Sanhedrin was made up of elements that didn’t always get along together. There was the family of the high priests. There were the Pharisees, and the Sadducees.
After the other two groups had tried unsuccessfully to get Jesus to say something they could use as evidence for putting him to death, it was time for the Sadducees to take a crack at it. Let me give you what bought the Sadducees into existence.
King David had promised the throne after him to his son Solomon, but when he was dying in 980 B.C. an upstart son Adonijah raised a private army, and began acting like he was king. But when Solomon’s mother, Bathsheba, complained about this, David commanded his priest Zadoc to crown Solomon king. Feeling that Adonijah would kill him for it, Zadoc anointed Solomon king. Surprisingly, the whole nation rose up, shouting , “Long live King Solomon!” With that, Adonijah had to flee for his life.
From that time on it became a sacred tradition with the Jews that only a direct descendant of Zadoc could be anointed high priest. It went on that way until 154 B.C when the only available descendant of Zadoc was an imbecile. So, the nation departed from tradition, choosing Jonathan, the younger brother of Judas Maccabeus as high priest. And, different group reacted to that in different ways.
One group of traditionalist went off to live n caves over the Dead Sea. They were the Essenes, who left us the Dead Sea Scrolls. A more prominent group of traditionalists
stayed on as a permanent group of separatists. We know the Separatists as the Pharisees.
The boyhood friends of Jonathan used his position to gain for themselves the wealth that came with managing the temple. They made a joke out of what is meant to be a descendant of Zadoc. They were saying, “Zadoc was high priest, and so is Jonathan; so by reason of sharing that office Jonathan is a descendant of Zadoc, and we friends of Jonathan are the Zadoc-ites.” That name, Zadocites, was softened to be pronounced as Sadducees.
When the Sadducees called themselves the descendants of Abraham and Jacob, Jesus used that to make them see that they actually believed in an afterlife. He made them realize that they thought of Abraham and Jacob as still being alive. In that way it proved to them that they did believe in life after death.