We sometimes lump together the Pharisees and Sadducees, but they were two distinct sects of Judaism. One of the differences between them was that the Sadducees did not believe in the possibility of the resurrection from the dead, and of course, that is why they are sad, you see?
The Sadducees are mentioned in the first reading from the Acts of the Apostles (5:17-26) along with the Sanhedrin. Peter and other disciples are meant to go on trial before the Sanhedrin because they have been preaching salvation found in Jesus Christ, risen from the dead. The disciples are in prison awaiting trial when an angel in the middle of the night opened the doors of the prison, releasing them and giving them this directive: “Go and take your place in the temple area, and tell the people everything about this life.” In a sense, this escape from prison is like a quasi-resurrection: leaving the tomb/prison with new life while there were guards stationed outside.
“Go and take your place in the temple area, and tell the people everything about this life.” What is everything to tell about this life? We hear it in the gospel reading from St. John's Gospel (3:16-21): “God so loved the world that he gave his only-begotten Son, so that everyone who believes in him might not perish but might have eternal life.”