top of page
  • Reuvan Chaim Klein

Tazria-HaChodesh: Old Month versus New Month ~ Rabbi Reuven Chaim Klein

Updated: Dec 2, 2022


This Shabbat we read Parshat HaChodesh, the last of four special Torah readings before Pesach. Parshat HaChodesh establishes Nissan as the first of the months of the Biblical Year. This is especially germane because this year we read Parshat HaChodesh on the day of Rosh Chodesh Nissan. So we discuss the first month of the year on the first day of that month. In this essay we will discuss two Hebrew words that both mean “month” — chodesh and yerach. We will strive to find the difference in their etymology and how/why they are used in different contexts.

Although some say that chodesh is Aramaic, while yerach is Hebrew, others offer a more sophisticated approach. The Malbim and Rabbi Samson Raphael Hirsch (1808-1888) provide a penetrating insight as to the etymology of the word chodesh. They explain that the primary meaning of the word chodesh is not “month” but rather “beginning of the month.” In this way we find that the word chodesh appears in the Bible when one would otherwise expect the phrase Rosh Chodesh to appear (see Num. 28:14, I Sam 20:18, and Isa. 1:13). The word chodesh, therefore, primarily refers to the concept of chadash (“new”) or chiddush (“novel” or “renewal”), and specifically denotes the novelty of the month. That chodesh also refers to the idea of a “month” is only a secondary, borrowed meaning.

What, then, does the word yerach mean? Malbim explains that the word yerach simply denotes a period of thirty days — regardless of whether or not those thirty days represent an astronomical event related to the moon. However, in truth, the word yerach is actually related to yareach (“moon”), whose lunar movements help us define the duration of a month. Based on this we may posit that while chodesh denotes the beginning of the month, yerach denotes the entire month as a whole.

Rabbi Aharon Marcus (1843-1916) writes that the word yerach is related to the Hebrew word oraiach (“path”) and to the Aramaic word itrachish (“it happened”). He does not explain the thematic link between these words, but to me it seems fairly clear. The word chodesh is related to the idea of “new,” and alludes to G-d’s role in administering the world, in which He introduces new occurrences that are outside of the normal system of nature. We call these events “miracles”. For this reason, the first of the months is Nissan, whose very meaning is “miracles” because the Exodus from Egypt, one of the greatest miracles of all time, happened then. In general, we use the word chodesh colloquially, because we wish to focus on G-d and His awesome miracles. On the other hand, the word yerach is less commonly used because it is related to the word for “path” and does not connote anything “happening” beyond the regular system of nature. When we refer to a month with the word yerach, we refer to time running its course in a natural way, as if to say that it just “happened,” seemingly without G-d’s miraculous intervention.

Rabbi Hirsch offers another way of differentiating between chodesh and yerach which fits with our model. He argues that the word chodesh denotes the idea of a month as simply a unit of time (measured by the amount of time it takes the moon’s light to disappear and reappear). In this way, the word chodesh is transcendental, or abstract. On the other hand, he explains, the word yerach connotes the month as a vehicle for maturation. That is, the word yerach implies a physical manifestation of the passage of time — more specifically, in the growth of produce. According to this understanding, the word yerach refers to a month in a very tangible or physical context, a month that is bound to the rules of nature.

Rabbi Mordechai Jaffe (1530-1612), the author of the Levush, writes that the custom is to refer to the month on a divorce document (a get) as a yerach, and on a marriage document (a ketubah) as a chodesh. He explains that this is because the word yerach is associated with being sent away, geresh yerachim (Deut. 33:14), while the word chodesh is associated with something new, and marrying a woman is called “taking a new wife” (Deut. 24:5). (It is also unfortunately true that many marriages end when the novelty wears off and a couple is left in a stale rut. The hope that this will not plague the newlyweds is reflected in the word chodesh that appears in the ketubah.)


Share this:

21 views0 comments

Recent Posts

See All


bottom of page