If one adds a commandment to 613, we get 614 or "tarid" commandments. "Tarid" is a language meaning descent as in "yeridah." This teaches us that if one comes up with his own innovation and adds a commandment to our perfect Torah even if he means to praise or glorify the Torah with this addition, he instead sullies the Torah because it shows that the Torah is based on man's intellect and is thus not divine. An addition puts into question the divine authenticity of the entire Torah which may likewise be construed as man-made and not the work of the King of kings.

Similarly, if one subtracts a commandment from the Torah, we would have "tariv" (612) commandments instead of 613. "Tariv" indicates fighting. Fighting and quarreling would ensue between Jews because certain groups would endeveor to eliminate specific commandments and other groups different commandments. Some are strong in particular commandments but weak in others and would therefore wish to eliminate those commandments that spotlight their weaknesses. And what is a weakness to one in Israel may be a strength to another. No consensus could be gotten to decide which commandment would be eliminated and fighting would be inevitable. Therefore taking one commandment away from "taryag" would lead to "tariv."

The prohibition of the addition or subtraction of commandments is learned "memenu" or from the fact that we have exactly "taryag" commandments in the first place. Even if one's motivations are proper, adding extra commandments leads to a downfall and subtracting commandments lead to fighting.