Traditional Jewish legal exegesis reads that verse in a very specific way. What it really means to say, later scholars hastened to explain, is that no prophet may add laws claiming that they are in the Torah, nor may individuals add or subtract details in any of the commandments. (My thanks to the JPS Commentary series for outlining this perspective so clearly.) In other words, we need to know our sacred text well enough to know when it's being adapted inappropriately.

Another interpretation hangs on the fact that this instruction concerning addition and subtraction of Torah teachings appears in the middle of a passage about the worship of other gods. This can be read to show that it is primarily an injunction to eschew idolatry. If the primary statement which underlies Torah is "I Adonai am your God, who brought you out of the land of Egypt, the house of bondage: You shall have no other gods besides Me," then it is of utmost importance that we not fall into the trap of equivocating about (or adding to) those particular words.

In the essay Paradoxes of Canon and Authorship in Ancient Israel, Bernard Levinson offers some context. He points out that "You shall not add anything to what I command you or take anything away from it, but keep the commandments of Adonai your God that I enjoin upon you" is a recognizable legal form used throughout the ancient Near East. Text like this was once used to prevent royal inscriptions, sets of laws, and treaties from being altered. Our challenge, of course, is reconciling this "fixity and textual sufficiency" with our need for our religious canon to address the needs of our day:

[L]ater generations face the conflicting imperatives of subsuming their lives to the authority of the canon while adapting that unchangeable canon to realities of social, economic, political, and intellectual life never contemplated at the time of its composition...By means of exegesis, the textually finite canon becomes infinite in its application. One of the chief means, therefore, by which a religious tradition demonstrates its creativity is the variety of ways it finds to accommodate itself to and overcome an authoritative yet textually-delimited canon.

Maybe the injunction against modifying God's commandments is a kind of koan. The text tells us not to augment or modify the word of God -- and yet it's arguable that in trying to concretize God's speech, we can't help changing the nature of that speech, if only into something we can fully express and understand.

God's words are infinite; ours are necessarily finite, as our minds and consciousnesses are finite. When we connect with God, however briefly, we touch a kind of transformation that ordinary language and interpretation can only approximate. "I am Adonai your God..." is our attempt to encapsulate the Sinai experience in words, to express the inexpressible reality of what it feels like to be permeated with the deep awareness of God's presence and uniqueness. Maybe that reality is the real "commandment" we are forbidden to modify...and we do the best we can to comply, though the fact of putting that reality into words means we're always already modifying it somehow.

As Ben Ben Bag says (in Pirke Avot 5:25), "Turn it and turn it over again, for everything is in it." Sure enough, the deeper we look the more we can find here. One way of turning (and re/turning to) the text is looking at it through a new metaphorical lens, and in this day of computers and internet, there's a whole crop of new metaphors for our interactions with holiness.

Today we can understand Torah as a document which contains within itself the seeds of its own transformation. When I download new software onto my computer, often as not that software comes packaged with the software necessary to "unpack" or "unStuff" or "unzip" itself. Just so, new Torah insights often hide within other interpretations, condensed and waiting to unfold. And that multiplicity of interpretations -- how a text which appears to be simple and singular can actually prove multilayered and ever-changing -- is a fundamental part of how we as Jews interact with Torah, even with those parts of Torah which at first glance appear to contradict the notion of multiple layers of meaning. As Levinson writes,

Properly understood, the canon is radically open. It invites innovation, it demands interpretation, it challenges piety, it questions priority, it sanctifies subversion, it warrants difference, and it embeds critique.

Or, as Rabbi Ismar Schorsch wrote in his commentary on parashat Beshalach a few years ago:

We tend to think of revelation as a highly restrictive term. The fate of a revealed text is to be immutable. We humans have no right to alter what God has given. But in Judaism precisely because the Torah is revered as divine, it becomes susceptible to unending interpretation. It would be a denigration of God's word to saddle it with just a single meaning. In contrast to human speech, which carries a finite range of meanings, the language of God was deemed to be endowed with an infinity of meanings. This theology freed the Rabbis to do midrash, creating the anomaly of a canon without closure. The vessels kept changing their contents. New challenges elicited new insights into a text inviolable only on the surface.

Amen v'amen.