The final verse of Matthew 7:1-6 seems to be completely unrelated to what precedes and follows. Not surprisingly it has generated many different interpretations. Throughout church history it has been interpreted as a prohibition against serving communion to heretics or the unbaptized, as a principle concerning how much energy to spend evangelizing those most resistant to the gospel, and even not interpreted as all because there is not enough context for it to make sense. There is no simple solution.
There is one approach that tries to relate it to the previous section by reading it as a sort of counterpoint to the message about judgment. David Allison summarizes the relationship between the passages this way: “Matt. 7:1-5 has commanded that there be not too much severity. Matt. 7:6 follows up by saying that there should not be too much laxity.” The kingdom and its principles are things of value like the sacrificial meat and pearls in the illustration. On this reading, Jesus is saying, “Don’t treat the kingdom and its principles casually.” The focus is not on trying to identify specific people with the dogs and swine (e.g. Gentiles, heretics) but rather on the action that shows a lack of treasuring something precious.
In a way, in judgmentalism we misuse the kingdom principles by overvaluing them. We wield them as weapons to judge and rank others according to their adherence to the kingdom life. This is a danger.
But there is an opposite danger: we can regard the kingdom principles too lightly. We can treat behaviors and attitudes that are contrary to the kingdom ethic as insignificant, matters such as honesty, sexual morality, economic practices.
Both of these dangers are present and even prevalent in the church today. Some groups use their faithful adherence to the kingdom way as justification for pride and judgment of others less faithful. These groups fail the judgmentalism test and have missed the point of the kingdom.
Other religious groups have evacuated the Christian message of virtually all moral content except, usually, for a few of the shibboleths of the contemporary culture such as environmentalism or intolerance. But the passage makes clear that we are to be involved in helping our kingdom siblings with the splinters in their eyes, not blithely denying the existence of them. Interestingly, those who treat kingdom purity so lightly often find that, as the passage predicts, it comes back to bite them in some way.
Taken together, then, the instructions in this section direct us toward a balanced way of thinking about and applying kingdom principles and purity.