Midrasch zu Jechezkiel 40:3
וַיָּבֵ֨יא אוֹתִ֜י שָׁ֗מָּה וְהִנֵּה־אִישׁ֙ מַרְאֵ֙הוּ֙ כְּמַרְאֵ֣ה נְחֹ֔שֶׁת וּפְתִיל־פִּשְׁתִּ֥ים בְּיָד֖וֹ וּקְנֵ֣ה הַמִּדָּ֑ה וְה֥וּא עֹמֵ֖ד בַּשָּֽׁעַר׃
Und er brachte mich dorthin, und siehe, da war ein Mann, dessen Aussehen wie das Aussehen von Messing war, mit einer Flachslinie in der Hand und einem Messrohr; und er stand im Tor.
Bereishit Rabbah
Rabbi Yehoshua Ben Levi said in the name of Rabbi Levi: Six things are required for building--water, dirt, wood, stone, rods, and iron. If you say he is rich, and does not need rods, he still needs measuring rods, as it says (Ezekiel 40:3): "with a line of flax in his hand, and a measuring rod". The Torah preceded these with six--"the first", "of old", "forever", "from the start", and "from the first" which is two, in the portion (Proverbs 8:22-23): "God made me as the beginning of His way, the first of His works of old. I was set up forever, from the start, from the first of the Earth."
Ask RabbiBookmarkShareCopy