I basically have two observations. First observation: People think they’re so clever to come up with paradoxes and questions to “stump the teacher,” creating these convoluted scenarios in their smug pride, thinking that they’ve won the day. Jesus shows them several things:
First, they are wrong about some of their presuppositions. The Sadducees didn’t believe in the resurrection of the dead, but Jesus is letting them know that there certainly is one. Secondly, the Sadducees didn’t believe in angels either, and Jesus is letting them know about their existence. One has to start from the correct point to reach the truth at a later point. Incorrect assumptions lead to skewed conclusions. And in all their smug hauteur, they were wrong about some of their premises, let alone in their thinking processes. There is truth, and not just opinion, about spiritual things after all.
Second, their scenario doesn’t “stump the teacher.” Even in their tangled tale, Jesus is able to give them a legitimate answer to their question. Since he knows first hand about this life and the next, he is able to answer with aplomb. “Let me tell you what’s it’s like on the other side…” He uses the context of what they regard as valid (the Pentateuch) to make his point. There are legitimate answers to all legitimate questions.
Second observation: The afterlife is real. The Sadducees, by theology and reason, had concluded that this life was all there is. Jesus lets them know by Biblical evidence and reason that there is more, and that life there is not just a candid or crude continuance of what we know. Despite some continuity with life here, it’s another mode of existence altogether. He still makes clear that it’s not for all, but only for those who respond properly to the message of the gospel as children of God and children of the resurrection.