What is "Ari'el"?
Targum Yonasan: The Mizbe'ach of Hashem. Rashi - also Yechezkel called it so - "veha'Ari'el Shteim Esre 1 " (Yechezkel 43:16), because Heavenly fire crouched on it like an Ari (lion) (Yuma 21b).
Rashi citing Midos 4:7: This refers to the Heichal. It was narrow in back, and wide in front (the Ulam, just like a lion is wider in front (its face)).
Malbim: It is Yerushalayim.
Radak: "Umeha'Ari'el ul'Ma'alah ha'Keranos Arba" (Yechezkel 43:15).
Why is "Ari'el" repeated?
Radak #1: This is like people who wail; they repeat themselves. The Navi groaned over it.
Radak #2: The second Ari'el is Samuch to Kiryas (Ari'el of the city). Kiryas is not Samuch to Chanah; it should say Kiryah, just there is a Sov in place of the Hei, like "Chalas Matzah Achas" (Vayikra 8:26), "Chamas Lamo" (Tehilim 58:5), "Tzitzas Novel" (above, 28:4) and similar verses.
Malbim: Yisrael itself is esteemed - it is the strength of Yisrael and their Gevurah - and also due to its king; David lived there.
Why does it say "Kiryas Chanah David"?
Rashi citing Targum Yonasan: It was built in the city in which David dwelled.
Radak: Refer to 29:1:2:2. It mentions David, for he first saw the place of the Mizbe'ach in Har ha'Moriyah, and offered a Korban there, and Hashem answered him with fire and the plague stopped.
Malbim: Refer to 29:1:2:3.
What is the meaning of "Sefu Shanah Al Shanah Chagim Yinkofu"?
Rashi: Your sins keep getting stronger, until your festivals will be cut off. Yinkofu is like "k'Nokef Zayis" (24:13).
Radak: What they offer there now is not accepted - "Oloseichem Lo l'Ratzon" (Yirmeyah 6:20), since their deeds are evil. They offer also to other gods. One who slaughters there is considered as if he is Nokef it and breaks the back of its neck - "Zokef ha'Seh Oref Kelev" (below, 66:3). Chagim are lambs, like "Isru Chag ba'Avosim" (Tehilim 118:27); the lambs that they slaughter, it is as if they break their necks. The Targum of "va'Arafto" (Shemos 13:13) is v'Sinkefei (the same root as Yinkofu). They add to come every year to offer Korbanos - they are not Korbanos!
Malbim: Yerushalayim should have engaged in fear of Hashem and His Avodah. Just the contrary, they added years, as if their life is primarily to add years, and not to acquire perfection. Their years are surrounded with festive days and Simchah of folly.
