This is the one-hundredth vocabulary word we have looked at, one by one, since this series of discussions began three years ago. And it is pretty ironic that it happens to be a word in Hebrew that just about everybody knows: "lo." There are two different words with the same pronunciation. When lo is spelled "lamed-vav," it means "his." But the far more familiar spelling is "lamed-aleph," and it means "no."

As human beings in general and as Jews in particular we have a love-hate relationship with the word "lo." On the one hand, if it weren't for this little word of two letters and one sound – about as small as a Hebrew word can get – we would be without seven of the Ten Commandments, the foundation of Jewish morality. On the other hand, if it weren't for this little word, we could get away with a lot more stuff.

I cannot tell you exactly or even approximately how many times the word "lo" appears in the Bible or, for that matter, in the siddur. I suspect it is one of the most frequent. It goes against our independent streak, which may be exactly the point. Without the boundaries that are established by a well-placed "lo," we would like be outside of relationship with God and most certainly outside of relationship with others. "No" is necessary for us all.

But the fact is, it is not only that "no" is necessary for us, it is also necessary by us. As aggravating as the insistent "no" of a two-year-old can be, it is also the beginning of self-reliance. As threatening as the belligerent "no" of dissent can be, it is also the beginning enlightenment. As frustrating as the reluctant "no" of a romantic partner can be, it is also the beginning of mutual respect.

Of course, there are unnecessary "no's" as well. Those are better described in a sermon than a lesson, and maybe some day I will do just that. For now, what is important is that "lo" brings us to a full stop in whatever direction we are moving. "Lo" makes us look around at the status quo and miss nothing. As a word of prayer, that is probably its most important function.