today's other readings are Tobit 3 and Psalm 25
It is not hard to see the link between the second half of our 1st reading and our gospel. We first hear of the story of Sarah, who has been married 7 times but each time, on her wedding night, the demon Asmodeus kills her new husband. In our gospel we hear of the Sadducees approaching Jesus with a similiar story, trying to trip Him up to recognize that there can be no resurrection of the dead.
Jesus counters this story by showing the Sadducees that the very sources of the Law that they cherish so much - Abraham, Isaac, Jacob and for that matter, Moses-- are alive because God, Yahweh, claims them as their God (see Exodus 3: 1-6). He is the God not of the dead but of the living. The Sadducees, who assume they know God and the Law better than anyone else, have failed to understand that Scriptural passage from Exodus. Jesus' words to them is a warning that when each one of them would die, they would encounter a living God.
This story reminds of me of the many people I havve encountered who have no time for organized religion or for that matter, for the notion of any sort of Deity. I like to ask them, so what do you think will happen to you when you die? The common answer I get is nothing - nothing will happen. Which then leads to a discussion, sometimes a bit heated. In the end, my final comment is "Well, be prepared for a shock when your time comes". For we believe in a God, and we know that our God, is the God of the living.