Was "Chatas Yehudah" one particular sin?
Sha'arei Teshuvah 1:27: It includes many sis.
Why does it say "b'Et Barzel"?
Rashi: This is a metaphor. It is carved out and recessed; it is not easy to erase.
Rashi citing a Midrash: This refers to Yirmeyah, who is called "Amud Barzel" (1:18).
Malbim: It writes on the margin above.
What is "b'Tziporen"?
Radak #1: It is with a stylus. A person engraves with his fingernail. There is no difference between engraving with one and with the other.
Radak #2: The stylus is called Tziporen. A Midrash says, He took an iron Tziporen and engraved with it.
Why does it say "[b'Tziporen] Shamir"?
Rashi citing a Midrash: This refers to Yechezkel, to whom Hashem said "k'Shamir Chazak mi'Tzurah Nasati Mitzchecha" (Yechezkel 3:9).
Radak: This is strong iron, just like a strong rock is called Shamir - "k'Shamir Chazak mi'Tzurah Nasati Mitzchecha" (Yechezkel 3:9). Targum Yonasan of "mi'Tzur ha'Chalamish" (Devarim 8:15) is mi'Shmir Tinra. The prefix Beis in b'Tziporen applies also to Shamir; it is written with an iron stylus, and a fingernail, and [on] a strong rock. After mentioning the Kli used to write, it must mention on what it writes. Even though it says "Al Lu'ach Libam", [Shamir] teaches that their heart is Shamir and strong; elsewhere it is compared to rock - "v'Hasirosi Es Lev ha'Even" (Yechezkel 11:19).
Malbim: The pen writes on top, and Tziporen Shamir engraves deeply. I.e. they sinned both in visible deed, and in the mindset of the heart and Nefesh.
What is "Charushah"?
Rashi: It is carved like one who is Choresh (plows) deeply.
Radak: This is like Charusah - "Charus Al ha'Luchos" (Shemos 32:16).
Why did He say "Al Lu'ach Libam"?
Rashi: They do not forget their idolatry.
Radak: It is as if their sin is written and engraved on their heart with an iron stylus, that it cannot be erased from their heart. What is carved into stone lasts forever - "b'Et Barzel v'Ofares La'ad ba'Tzur Yechatzvun" (Iyov 19:24). It mentions lead, for one fills engraved writing with lead so the sides of the engraving will not be break and the form of the letter will be broken
Why does it say "Libam" (third person) and "Mizbechoseichem" (second person)?
Radak: Many verses are like this. It teaches that your sins are engraved in the corners of your Mizbechos, for they are your sins 1 . The prefix Lamed in "l'Karnos" is in place of Beis, like the Lamed in "Lifneichem l'Charev" (Vayikra 26:7), "Haragti l'Fitz'i" (Bereishis 4:23), "Yashavta l'Chisei" (Tehilim 9:5) and similar verses.
I.e. they are altars to idolatry. (PF)
