Jesus teaches that there are greater and lesser applications of His law, but He does not do away with precision or carefulness. If you have ever had insects get into a beverage, that’s not something you just overlook. That’s something you’re going to want to do something about. What Jesus warns against is focusing on smaller things at the expense of larger things. But notice that, ultimately, He says to do both. If we neglect justice, mercy, and faithfulness, particularly in tithing, we miss the mark. But if we justify carelessness by saying it’s OK because we do the weightier matters, we also miss the mark.
When we look at God’s actions, whether in Scripture or His work in our own lives, we see that He does not neglect details for the sake of broad principles, but neither does He obsess over the details and lose the plot. His application is always complete and perfect, encompassing large and small, and that should be our goal as well.
In the same way, if our approach to leavening and unleavened bread only focuses on finding every last crumb, but we overlook the larger spiritual principles, we miss the mark. Both weightier things and little things matter.