What does Matthew 22:35 mean?

A group of Pharisees heard that Jesus' brilliant response to a challenge silenced the group known as Sadducees. This more secular, political wing of Judaism was a rival to the Pharisees. Despite their best efforts, they had no response to Jesus' profound and insightful answer (Matthew 22:23–33). Now the Pharisees appear to want another chance to test Jesus. They pick one of the brightest and most educated of their number to ask Him a hard question. This man is unnamed, but he is a Pharisee and described as a lawyer. In this context, a "lawyer" is someone well versed in Scripture and the traditions built around it.

The "test" here is subtly different than the earlier ones. Those were explicitly designed to trip Jesus up: to trick Jesus into saying something that could be used against Him. The "test" contained in this question seems more aimed at wanting to know how Jesus will answer a hotly debated issue among the religious leaders themselves. It's potentially controversial, but it's not a "bad" question, at all.