You shall not add to the word that I command you, nor take from it, that you may keep the commandments of the LORD your God that I command you.
There are two dangers mankind always confronts when handling the Word of God. The first danger is to add human constructions to it that are viewed as equal to it. The second danger is to diminish scripture by taking away from its authority. These are both equally dangerous.
Moses warned Israel that both extremes would not be the way to "keep the law" given to them. They needed to guard their hearts from these tendencies. Respect for the God of Israel meant at a practical level honest love and respect for the Word of God. God had revealed His will and ways in His law. They would serve God by not adding or taking away from it.
And the history of Israel eventually led to a dismissive attitude toward this command. The Jews of the First Century had groups that put high regard on oral traditions of the Rabbis. Some invested those traditions with the authority of scripture. Others denied the authority of much of the Old Testament and thus also disobeyed this command.
Both types of groups rejected the "Word made flesh" in Jesus. So disrespect for God's Word defined the generation of Israel of Jesus' contemporaries. This was ultimately a disrespect for God, as shown in the gospels in the way Jesus was treated.
- Posted with my iPad. The Apple Kool-Aide tastes fine.