Legalism is dangerous because it attempts to lower others in the attempt to elevate oneself, ignoring the very issues of impurity within one's own life. A careful study of the Pharisees demonstrates that they were not all bad people. In fact, in many ways, the Pharisees were actually trying to increase the people's sensitivity to God by constructing rules that would keep God more visible. The fatal flaw in their thinking was that they believed holiness could be brought about or achieved through outward cosmetics. So they started writing laws that would prohibit people from "eating" this or that, or associating with "this" person or "that" person. Again, it was all done in the hopes that these rules or regulations would somehow bring about a form of holiness. Did they succeed? Well, not exactly. It got so bad that many of the Pharisees could not follow their own rules and regulations, which turned them into real phonies, distancing them from God. Jesus pointed out that the aftermath of such rules only led to the Pharisees cleaning the outside of the cup (the exterior) while neglecting the interior (the heart) - which was most important. And worst of all, their self-governed rules prevented others from seeing the true nature of God and His love for people.
I love what Mark Batterson , Pastor of National Community Church, wrote as it relates to this topic -
"We need to be people who transform our culture and not condemn it."
Legalism serves only as a fantasy step toward holiness. Don't be fooled by imitations. Unfortunately, there are still people leading churches today who spend a lot of time waxing the outside of their cup while constructing negative statements about the world. That's not the shine that Jesus was talking about.
If you're feeling crushed by the weight of legalism, turn to the teachings of Jesus. Certainly, God doesn't love you less when you blow it or miss the mark. Conversely, God doesn't love or approve of you more when you surpassed the holiness of Mother Theresa. It doesn't work that way!
For a deeper study on this, go to Matthew 7 (how to avoid hypocrisy).
