What does Matthew 23:24 mean?

This passage illustrates the central problem of the scribes and Pharisees, both in their practice of Judaism and how they imposed it on the people. They went to the trouble to give the required ten percent of the smallest of the garden "crops," even tiny herbs. That was fine, but they obsessed over these details, while missing the big reasons behind God's law for His people: justice, mercy, and faithfulness (Matthew 23:23–24).

In other words, these spiritual leaders did not interpret the law to the people in a way that emphasized what God really cared about. To use a common English expression, they "missed the forest for the trees:" they forgot that details are meant to form a larger picture. They focused on wooden, legalistic religious performance in a way that ultimately only served their own pride, power, and glory. Jesus once again calls them blind guides (Matthew 23:16–17), meaning they have no understanding of where they are leading God's people.

This obsession with legalistic details is compared to someone who uses a screen to keep insects out of their drink, while failing to notice a massive animal floating in there. It's a humorous and devastating line. Both gnats and camels were unclean for the Israelites to eat. To avoid even accidentally eating something ritually unclean, Pharisees would use cloth to strain their drink. Like tithing from their herb crop, this was exacting work performed to be religiously perfect.

The scribes and Pharisees could not—or would not—see they were missing the much more important reasons behind God's regulations for His people. Obeying specific commands is important, but details are not meant to override the broader message being given by God.