Zeal without knowledge puts one in great spiritual danger, and we see this demonstrated in Jesus’ clashes with the Pharisees and scribes regarding their extrabiblical traditions. No one could question the zeal of these sects to keep God’s law. So concerned were they to make sure they did not violate the Lord’s commandments that they developed what they called a “fence around the law” consisting of various regulations designed to help ensure that the Mosaic law was obeyed. They reasoned that people would certainly be innocent of transgression by observing those extra regulations. Judaism’s system of kosher laws is a classic example. (Modern Judaism is based more on the traditions of the rabbis than on the Old Testament.) Exodus 23:19; 34:26; and Deuteronomy 14:21 all say, “You shall not boil a young goat in its mother’s milk.” Over time, the kosher law that milk and meat products should not be eaten together developed out of a desire to keep the commandments of these passages. After all, if one never puts meat and milk together, one will certainly never boil a young animal in its mother’s milk, even accidentally.
That extra rule is legalistic enough, but even worse are rules that end up causing direct transgression of the commandments. Legalism is a problem because misplaced zeal for the law can lead one to violate the law without even realizing it. One tradition of the Pharisees, the Corban rule to which Jesus refers in today’s passage, took a good thing—giving gifts to the temple—and turned it into a means by which God’s law was broken. One commentator likens the Corban rule to the modern practice of deferred giving, which allows individuals to deed property and other gifts to another at death while retaining control over the gift in the meantime. Under the Corban rule, Jews could pledge something to the temple and have it pass into the temple’s possession at their death, but while the givers lived, they stewarded the property and lived off its proceeds.
In itself, such a rule was not evil and in fact could be a good thing. The problem was that the Pharisees and scribes were allowing people to use the Corban rule to escape their obligations to other parts of the law. According to the Corban rule, men and women who made gifts to the temple in such a way were free from having to support their elderly parents. This broke God’s command to honor our fathers and mothers (Mark 7:9–13).