Halakha 1 Raja-raja 6:7: Mishneh Torah, The Chosen Temple & Shulchan Shel Arba

The Temple is to be built with large stones or bricks if large stones are not available. The stones are not carved on site, rather they are carved and dressed away from the Temple Mount and brought in afterwards, as it says "Large, expensive stones for the foundation of the House, hewn stones" and it [also] says "the sound of the axe, nor any other metal tool was heard in the Temple while it was being built."

Any stone that was chipped enough to catch the fingernail [to the same exacting standards] as with a shechita knife, in unfit for the ramp and for the altar as it says "With whole stones build the altar of God." Where did they get the stones? From virgin ground. They would dig down to where it was obvious that this soil is not for cultivating or building and take out whole stones, or they would take rocks from the Mediterranean Sea and build with those. Similarly, the stones of the Temple and the Courtyards were also whole.

One also has to careful when about to say birkat ha-mazon to remove the knife from the table. The reason for this practice is because the table is called an “altar,” and just as on an altar we have been warned not to brandish something made of iron over it, as it is said, “do not build it [an altar] of hewn stones, etc.”¹⁹⁴Ex 20:22. The rule of Torah is that if one makes it into an altar of hewn stones with a tool of silver or flint, it is permitted. For the point of the prohibition is not against it being hewn, but rather because it is hewn with something made of iron, i.e., a sword, and Torah kept it far from the tabernacle, when it is written: “gold, silver, and copper,”¹⁹⁵Ex 25:3. but does not mention iron there. And likewise with the sanctuary it is written, “No hammers or axe or any iron tool was heard in the House when it was being built.”¹⁹⁶I Kings 6:7. The reason is because that is the power of Esau with what he was blessed from his father’s mouth; this is what is meant by “By the sword you shall live,”¹⁹⁷Gen 27:40. and it is written, “but Esau I hated.”¹⁹⁸Mal 1:3. Therefore it is kept far from the sanctuary. And likewise at the table we have been warned to remove the sword from it, because the sword is something destructive¹⁹⁹The pun ha-herev hu ha-mahriv is lost in the translation. and the source of destruction, the opposite of peace, and it does not belong in a place of blessing, i.e., peace. For indeed the altar and the table prolongs a person’s days, while a sword shortens them, and it makes no sense to brandish something that shortens over something that prolongs life.²⁰⁰Mekhilta Yitro (end).