What is the significance of your profaning it?
Radak: This is the opposite of the Goyim, who honor and aggrandize My name. Is there a greater Chilul than saying "Shulchan Hashem Megu'al Hu", i.e. it is disgraced?
Malbim: You profane Hashem's name via saying "Shulchan Hashem Megu'al Hu." You offer to Hashem Himself, and not to those who serve Him - if so, His table is the Mizbe'ach, and it is dedicated to His name. If so, it is proper that you honor it - you do the opposite!
What is the meaning of "v'Nivo Nivzeh Achlo"?
Rashi: The Niv (adage) of the Mizbe'ach fluent on your lips - you say constantly that its food is disgraced. You established this bad saying about My Mizbe'ach.
Radak #1: Niv is saying, like "Niv Sefasayim" (Yeshayah 57:19). The Kohen who offers, he constantly says that the Mizbe'ach's food - Chelev and blood - is repulsive and disgraced.
Radak #2: Niv is like Tenuvah (produce).
Radak #3: It (the Mizbe'ach) is disgraced, and its gifts are disgraced from it.
Malbim: There are two matters of the Mizbe'ach. (a) Matters offered on the Mizbe'ach, such as Chelev and blood - you say that this is Megu'al. (b) Nivo is the fruits and yield of the Mizbe'ach - Kodesh meat that the Kohanim eat, e.g. Chatas and Asham, and meat that the owners eat (Kodshim Kalim) from Hashem's table. You say that this is disgraced.
