387. Restraining Order: The prohibition against straying after our urges
…and you won’t stray after your hearts and your eyes, which can lead you astray. (Numbers 15:39)
This mitzvah continues from the line of reasoning underlying tzitzis, in the previous mitzvah. We are commanded to wear tzitzis so that when we see them, we will remember God’s commandments and do them, as opposed to straying after the desires of our hearts and eyes. “Do all of God’s commandments” is one of those general catch-all phrases that doesn’t count as a separate mitzvah but “Do not stray after the desires of your hearts and eyes” is a very specific prohibition.
The gist of chasing after one’s hearts is not to pursue philosophies that are antithetical to Torah, since doing so ends up confusing our minds with heretical ideas. If an idea that is counter to Torah should pop into one’s head (for example, What if so-and-so really is “god?”), one is not supposed to pursue it. Rather, the appropriate course of action is to nip it in the bud and focus one’s efforts on Torah.
Not pursuing the desires of our eyes is even more self-evident: it refers to giving in to all of our physical urges, especially those of a sexual nature. To reinforce this idea, the Talmud in Brachos (12b) cross-references our verse with Judges 14:3, in which Samson frames his desire for a particular woman in these terms. (It also cites Psalms 14:1 to support the use of hearts to express heretical thoughts.)
The reason for this mitzvah is obvious: if we give in to improper thoughts or urges, we will be led to sin. This mitzvah is the first line of defense to keep us from getting into even greater trouble. The Sefer HaChinuch compares the thoughts and urges to fathers and the resultant actions to children. Our job is to keep these fathers from reproducing. The mishna in Pirkei Avos (4:2) tells us that, left unchecked, a sin just leads to another sin, to another, to another, ad infinitum.
This mitzvah applies to men and women in all times and places. It is discussed in the Talmud in tractate Brachos, on page 12b. This mitzvah is codified in the Mishneh Torah in the second chapter of Hilchos Avodas Kochavim. It is #47 of the 365 negative mitzvos in the Rambam’s Sefer HaMitzvos and #156 of the 194 negative mitzvos that can be observed today as listed in the Chofetz Chaim’s Sefer HaMitzvos HaKatzar.