What is the meaning of "va'Ya'af"?
Radak: It is an expression of flying; there is Chataf Kamatz under the Ayin. "Va'Ya'af David" (Shmuel II, 21:15) has a Patach under the Nun; it is an expression of tiredness. I was astounded by the vision and noise. I thought that I will die.
Which Seraf was this?
Malbim: It was a special angel for giving Nevu'ah to Nevi'im.
Malbim citing Brachos: It was Micha'el, the Sar Tzeva 1 of Yisrael.
I.e. head general. In Daniel (10:21), he is called "your Sar."
What is "Ritzpah"?
Rashi: It is a coal. Also "Ugas Retzafim" (Melachim I, 19:6) is Ugas Reshafim (a cake baked in coals). Regarding Yeshayah and Eliyahu it is written with a Tzadi, to hint that Hashem said Ratzuz Peh (crush the mouth) that slandered My children. Yeshayah said "I dwell among a nation of Tamei lips", and Eliyahu said "Ki Azvu Verisecha" (Melachim I, 19:10).
Rashi (7) and Radak, from Targum Yonasan: It is words that he received from Hashem, to bring them to the Navi 1 . Malbim - even though the angel appeared as a Seraf, the Dibur was greater; it scalded the Navi.
Radak: Yonason translates the entire verse is a metaphor - 'descended to me one of the servants, and in his mouth was a saying from in front of the Shechinah on His throne of honor in Shamayim above, over the Mizbe'ach.'
What is "Melkachayim"?
Rashi: It is tongs.
Malbim, based on Targum Yonasan: This is a metaphor - just like people take a coal via tongs, lest it scald them, so the Seraf took Hashem's word without being harmed.
From which Mizbe'ach did he take the coal?
Rashi: It was from the Mizbe'ach in the Azarah. Malbim - it mentions the Mizbe'ach to teach that the Seraf atones for his sins, just like the Mizbe'ach.
Rashi (7), from Targum Yonasan: He took Dibur from Hashem from His throne in Shamayim, which is opposite the Mizbe'ach in the Heichal.
QUESTIONS ON RASHI
Rashi writes that "Melkachayim" is tongs. A Seraf could take the coal without tongs!
Rashi (7, from Tanchuma Vayishlach 2): Even so, the Seraf feared lest he be scalded. This shows Yeshayah's strength - the coal did not harm him! "Ki Rav Me'od Machanehu" (Yo'el 2:11) - these are angels; "Ki Atzum Ose Devaro" - Nevi'im are greater than them.
Radak citing his father: If the Saraf would touch the Navi's mouth with his hand, he would burn him.
