Мидраш к Йехезкэля 40:3

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."