The formula used in these verses is fairly typical of that used throughout our texts. However, our commentaries were puzzled by the use of the words “neither shall you diminish”, which is an expression not used before in any of our sacred texts. The text previously stated the warning to hearken to the statutes and ordinances, so why the qualification “neither shall you diminish”? One classic interpretation believes that by not adding to the observance anything which is not sanctioned by Torah there won’t be any diminution. However, once a person begins to add or alter the mitzvah, there is automatic diminution, as the Talmud says “kol hamoseef gorea”.
This becomes one of the classic arguments of those conservative interpreters of text that believe “chadash assur min hatorah”. Of course, their argument isn’t that black and white, because of Torah shel baal peh, the oral tradition and medrash, the quintessential qualifiers of the text. Text must be interpreted if it is to be spiritually meaningful to later generations wishing to fulfill the mitzvoth and understand the text
For example, the text references a veiled threat that if one doesn’t “hearken” unto the statutes he will die. The Ibn Ezra understands this literally, while Harav Kook disagrees with the Ibn Ezra’s understanding of life. For Harav Kook, life is not the opposite of death, but the opposite of a colorless and meaningless existence. It isn’t choosing between life and death as the Ibn Ezra believes, but choosing between a rich, fulfilling, spiritual existence rather than an empty life, void of spiritual meaning.
Harav Kook’s interpretation of the above text cast an entirely different meaning not only on the text but on our perception of godliness and how we ought to be relating to Torah.