Why Iron May Not Touch the Stones of the Altar

"And if you make Me an altar of stones" (Exodus 20:22) - this is an obligation. You say it is an obligation, but perhaps it is only optional? Scripture teaches, "You shall build the altar of the LORD your God of whole stones" (Deuteronomy 27:6) - an obligation and not optional. In the name of Rabbi Yishmael they said: every "if" in the Torah is optional except for three: "And if you make Me an altar of stones"; "And if you bring a meal offering of first fruits" (Leviticus 2:14); "If you lend money to My people" (Exodus 22:24). "You shall make for Me" - that their hewing, their bringing, and their building be for My name. "You shall not build them of cut stone" (Exodus 20:22) - that they not be sawn with a saw nor worked with a chisel. And from where do they bring them? They dig the virgin ground until they reach a recognizable place that has not been a place of labor and building, and they extract the stones from there; or they bring them from the sea, from the riverbed. Since it says, "for you have lifted your sword upon it and profaned it," one might think they are disqualified only if they were hewn with a sword. Scripture teaches, "you shall not lift iron upon them" - behold, iron is like a sword. If we are in any case to treat iron like a sword, what does "for you have lifted your sword upon it" teach? This is what Rabban Yohanan ben Zakkai says: why was iron singled out to be disqualified from all the kinds of metal? Because the sword is made from it, and the sword is a sign of calamity, while the altar is a sign of atonement. One removes that which is a sign of calamity from before that which is a sign of atonement. And are these things not a matter of inference? If of stones, which neither see nor hear nor speak, the Holy One, blessed be He, said "you shall not lift iron upon them" because they bring atonement between Israel and their Father in heaven, then how much more so the children of Torah, who are atonement for the world - that no harmful thing among all the destroyers in the world should touch them. "You shall not build them of cut stone" - them you do not build of cut stone, but you do build the Sanctuary and the courtyards of cut stone. One might think that if a single stone above was chipped the whole altar is profaned; Scripture teaches, "and you profaned it" - it is profaned, but the altar is not profaned. From here they said: any stone that iron touched, or that was chipped enough that a fingernail catches on it like a slaughtering knife, is disqualified for the altar and for the ramp. Another interpretation of "and you profaned it": from where do we learn that all the rites performed when the altar is disqualified are themselves disqualified? Scripture teaches, "and you profaned it."