Chodesh is the new moon, and by extension the month it begins. It shares its root, ch-d-sh, with chadash, new or renewed, and the picture is exact: the moon at chodesh is new every month and the same moon every month. Nothing is replaced; the same body is renewed and begins its cycle again.

This is why chodesh is the living illustration behind the new covenant. When Yirmeyahu (Jeremiah) promised a brit chadashah, the Hebrew ear did not hear a covenant scrapped and swapped for a different one. It heard the covenant renewed, the way the moon is renewed at every chodesh: the same, made fresh. Israel marked the chodesh as an appointed rhythm of the year (Numbers 28:11), a recurring renewal built into the calendar HaShem set.