What does Matthew 22:36 mean?

The tone of the exchanges between Jesus and the various groups of religious leaders gathered in the temple seems to be shifting. It started with attempts to trip Jesus up. Some chief priests asked Him about where His authority comes from (Matthew 21:23). Later, some Pharisees engineered a trap in asking about Jesus' stance on paying taxes to Rome (Matthew 22:15–22). Then the Sadducees attempted a logical trap, only to have it turned against them (Matthew 22:23–33).

Jesus answered everything asked of Him so profoundly and so meaningfully that the next question is merely difficult, not necessarily hostile. This "test" question (Matthew 22:35) may very well be entirely sincere, driven by interest in Jesus' answer. This well-educated scholar of the law asks Jesus to identify the "greatest" of the commands in the Law of Moses.

It seems this topic was regularly debated among religious leaders of that era. Which commands were light, and which were weighty? Which were most essential? Which one was the greatest in the entire law, meaning in all the Old Testament Scriptures? Perhaps the question is meant to be a trap only if Jesus answers it poorly. If that's the case, Mark's account of this exchange shows that the lawyer was not prepared for Jesus to say exactly what he himself would have said (Mark 12:28–34).