After the physical death of Jesus Christ, his apostles went on spreading his teachings; trying to convert others to believe. A group of people who they had difficulties with along the way were the Sadducees, who were a Jewish sect. The Apostles and Sadducees were unable to find a way to reconcile their rival opinions, which leaves the question: why were the Sadducees and Apostles unable to find a way to reconcile their rival opinions?
Trying to convert a group that has mostly different beliefs than you do is a long shot in many ways. First of all the Sadducees though they believed in God, did not believe in an immortal soul, and that there is life after death. Also they did not believe in resurrection(Christ rising from the dead), which was pretty fundamental to the teachings of Christ, which was now being carried out by His Apostles. This already would be a pretty large rift in the view points, and also from the sounds of it the Sadducees had a pretty firm belief on their own beliefs.
Not believing in resurrection meant that the Sadducees would not have been very convinced of Christ being resurrected, which was a message that the Apostles shared. Another thing that was a very important piece of the teachings of Christ was that humans have an immortal soul, which was again something that the Sadducees did not have a belief in meant that they would have also not been convinced with the Apostles teachings, when it came in regards to that.
One of the largest reasons why the Sadducees and Apostles were unable to find a way to reconcile their rival opinions, was because the Sadducees questioned that Christ was the Son of God. Because the Sadducees questioned or disagreed with many of the fundamental beliefs in the teachings of Christ, reconciliation between them and the Apostles was a bit out of reach to say the least. The Sadducees saw the Apostles most likely as people who were changing the old ways, which threatened their beliefs, regardless of if their beliefs were correct or not, in the first place. They saw the Apostles as a threat to their overall way of life.
The Sadducees and Apostles had quite a few rival opinions, on a variety of things including: the soul, resurrection, and the question of whether Jesus was the Son of God. The beliefs of the Apostles in many ways went against the beliefs of the Sadducees, which caused a rift between the two groups. To conclude, this was why the Sadducees and Apostles were unable to find a way to reconcile their rival opinions.