The Torah in Parashat Shoftim (16:22) issues the prohibition against erecting a “matzeiva” (“monument”), stating that this is something which the Almighty “despises” (“asher sanei Hashem Elokekha”). Rashi, based on the Sifrei, explains that the difference between a matzeiva – which the Torah forbids erecting – and a mizbei’ach (altar) – which the Torah requires erecting and using for sacrifices – is that a matzeiva consists of just a single stone, whereas a mizbei’ach is made of many different stones. Numerous writers sought to uncover the meaning and significance underlying this prohibition, and to explain this distinction drawn by the Torah between a matzeiva and an altar.
The Sheim Mi-Shmuel suggests an explanation based on the verse in Sefer Melakhim I (18:31) describing the altar that the prophet Eliyahu constructed at Mount Carmel, during his confrontation with the false prophets of Ba’al. Eliyahu used twelve stones for the altar, and the verse states that this number was chosen to correspond to the twelve tribes of Israel. The Sheim Mi-Shmuel suggests deducing from this account that the stones of the altar represent the merging together of the different groups among the Jewish People. No two stones are precisely alike, but they are all combined into a single entity dedicated to the service of God. The twelve stones of Eliyahu’s altar reveals the symbolic meaning of the altar’s sons – the notion of different groups and different streams joining together in the devoted service of God.
On this basis, the Sheim Mi-Shmuel writes, we can understand why God “despises” a single-stone matzeiva but commands us to construct an altar. A matzeiva signifies the individual’s service of God as an individual, as opposed to serving Him as one of a large group of distinct but unified “stones.” Serving God with a matzeiva reflects the notion of serving God in isolation, separate and apart from the rest of Am Yisrael, focusing exclusively on developing one’s own personal connection to the Almighty, without joining with others. We are to devote ourselves to God not simply as individuals, but as members of a large nation consisting of many different groups. And thus we are to aspire not only to excel personally in our observance, but also to influence and inspire all the other “stones,” so that we all come together to form a single “altar” in the service of our Creator.