‘And there came to him certain of the Sadducees, those who say that there is no resurrection,'
The Pharisees having been defeated in their attempts to discredit Jesus, the Sadducees now approached Him in order to dispute His teaching on the resurrection of the body. Like many Greeks they did not believe in such a resurrection. They did it by an appeal to levirate marriage. The principle of that is that if a man dies having no children to inherit his property, with the result that his wife is childless and has no one to care for her, His brother who lives in the same household should marry and impregnate the widow and thus produce seed to his brother's name (see Deuteronomy 25:5-10). The child will then grow up to look after his ageing mother, and to inherit the dead brother's inheritance. It is questionable, although not certainly so, whether levirate marriage was actually practised in New Testament days, but whether it was or not it had certainly been practised in the past, and was even more certainly spoken of in the Law.
This is the only mention of the Sadducees in Luke's Gospel, but see Acts 4:1; Acts 5:17; Acts 23:6-8. They do not seem to feature in Galilee and Peraea. We can only pick up something of what their teaching was from such passages as this, and from the literature of their opponents. They appear to have founded their teaching on the first five books of the Bible (the Torah, the Books of Moses), having a secondary view of the prophets. This included the rejection of the idea of either the resurrection of the body or of the existence of angels, which they saw as the newfangled teaching of some of the Prophets (Isaiah 26:19; Daniel 12:2) and of the Pharisees. They tended to be Hellenistic and to be politically tolerant of Rome. The leading priests were in fact Sadducees.