The Sadducees were a sect of Judaism in Jesus’ time who, amongst many other things, believed that there is no afterlife. They approached Jesus with a riddle to test the basis of Jesus’ teachings about Heaven. While it seems like they intended to trick Jesus with their question, he used it as an opportunity to describe a very crucial characteristic of God.
In the process of preaching about this portion of Luke 20, Pastor Tim Gaydos described a number of parallels between the doubt of the Sadducees and prevalent doubts in our own culture about the afterlife, the characteristics of God, and the saving power of Jesus.
27 There came to him some Sadducees, those who deny that there is a resurrection, 28 and they asked him a question, saying, “Teacher, Moses wrote for us that if a man's brother dies, having a wife but no children, the man must take the widow and raise up offspring for his brother. 29 Now there were seven brothers. The first took a wife, and died without children. 30 And the second 31 and the third took her, and likewise all seven left no children and died. 32 Afterward the woman also died. 33 In the resurrection, therefore, whose wife will the woman be? For the seven had her as wife.”
34 And Jesus said to them, “The sons of this age marry and are given in marriage, 35 but those who are considered worthy to attain to that age and to the resurrection from the dead neither marry nor are given in marriage, 36 for they cannot die anymore, because they are equal to angels and are sons of God, being sons of the resurrection. 37 But that the dead are raised, even Moses showed, in the passage about the bush, where he calls the Lord the God of Abraham and the God of Isaac and the God of Jacob. 38 Now he is not God of the dead, but of the living, for all live to him.” 39 Then some of the scribes answered, “Teacher, you have spoken well.” 40 For they no longer dared to ask him any question.
41 But he said to them, “How can they say that the Christ is David's son? 42 For David himself says in the Book of Psalms,
“‘The Lord said to my Lord,
Sit at my right hand,
43 until I make your enemies your footstool.’
44 David thus calls him Lord, so how is he his son?”