What does Matthew 22:26 mean?

Some Sadducees—a more secular, political part of the Jewish ruling class—are hoping to stump Jesus on the issue of human resurrection. They do not believe in an afterlife, or even a spirit world. To illustrate what they see as absurdity of life after death in view of the Law of Moses, they point to a requirement from Deuteronomy 25:5–10. If a married man dies without children, his brother must take the widow as his own wife and have a son with her. The product of this Levirate marriage is considered the son of the late brother. This would continue the family line of the man who has died.

Now the Sadducees begin to make their case. They pose a scenario with seven brothers, where the first brother married and then died without having any children. He leaves his wife to the next brother in line. Then, one by one, each brother dies without having any children with her, and the next brother dutifully takes her as his wife. In other words, all seven brothers were married to her at some point.

This, in the Sadducees' minds, creates an absurdity in the afterlife: a woman with seven husbands, or, at least, seven men with claims to that title (Matthew 22:28). Jesus will correct this misunderstanding in His response (Matthew 22:29–32)