Shekalim 18

 יופי לך מזבח

In the discussion of the mishnah about donations to the Temple, the subject of trees arises. The Gemara wants to understand the size of a tree used on the altar. It concludes that the fire on the altar was one cubit (אמה) by one cubit and the trees are sized accordingly.

In order to understand which altar the Gemara is referring to, we need to take a look at the different sizes of the altars in history. (We are of course referring to the large altar used for sacrifices, not the מזבח הקטורת .) The first altar was the one built in the desert, for the Tabernacle. Its dimensions were rather small: five cubits by five cubits and three cubits high:

שמות כז: א וְעָשִׂיתָ אֶת-הַמִּזְבֵּחַ עֲצֵי שִׁטִּים  חָמֵשׁ אַמּוֹת אֹרֶךְ וְחָמֵשׁ אַמּוֹת רֹחַב רָבוּעַ יִהְיֶה הַמִּזְבֵּחַ וְשָׁלֹשׁ אַמּוֹת קֹמָתוֹ

When King Solomon built his altar in the First Temple it was considerably larger: twenty cubits by twenty cubits and ten cubits high. (Note that the מזבח is always a square.)

 וַיַּעַשׂ מִזְבַּח נְחֹשֶׁת עֶשְׂרִים אַמָּה אָרְכּוֹ וְעֶשְׂרִים אַמָּה רָחְבּוֹ וְעֶשֶׂר אַמּוֹת קוֹמָתוֹ  . דברי הימים ב ד:א  

Even though this altar was considerably bigger than its predecessor, we see that it was not big enough for all the sacrifices offered at the dedication of the Temple:

 מלכים א ח: סד בַּיּוֹם הַהוּא קִדַּשׁ הַמֶּלֶךְ אֶת-תּוֹךְ הֶחָצֵר אֲשֶׁר לִפְנֵי בֵית-יְהוָה כִּי-עָשָׂה שָׁם אֶת-הָעֹלָה וְאֶת-הַמִּנְחָה וְאֵת חֶלְבֵי הַשְּׁלָמִים  כִּי-מִזְבַּח הַנְּחֹשֶׁת אֲשֶׁר לִפְנֵי יְהוָה קָטֹן מֵהָכִיל אֶת-הָעֹלָה וְאֶת-הַמִּנְחָה וְאֵת חֶלְבֵי הַשְּׁלָמִים. 

The altar reached its greatest size during the Second Temple. The mishnah in Midot (3:1) explains that it was thirty two cubits by thirty two cubits in size. After taking away space for the יסוד, סובב וקרנות we are left with a net space of twenty four by twenty four for the fires. This large space allowed for more than one fire to burn at a time.

Now it is clear that our Gemara can only be referring to מזבח המשכן, the altar in the desert. All the others were much bigger and a one cubit by one cubit fire would have been miniscule.

While the desert altar was the smallest and was used for the shortest period of time, it is the only one of which we have a concrete representation. Sadly, all traces of the vessels used in the First and Second Temples have disappeared. So have all the items used in the Tabernacle. However, one “homage” to the altar still exists: the altar that was uncovered at Tel Arad.

Tel Arad was a military outpost in First Temple Judah. It was a stronghold for hundreds of years. Its population of soldiers was rather devout, after their own fashion: they built themselves a mini-temple in their compound, complete with incense altars and מצבות :

In the courtyard of their temple, they put up an altar, and they strictly followed the Torah’s directions in building it: it was built of unhewn stones, filled with dirt, and measured five by five cubits:

Why has this amazing place survived when everything from the Temple in Jerusalem is gone? Because when King Josiah, as part of his religious reform, sent messengers to destroy this wayward temple, the residents decided to cover it up with the fortress wall instead. They put the temple in “genizah,” effectively preserving it for millenia! Perhaps not the Aradians intention but a great visual aid for us today.