Since the Torah will later command "va'Aseh Lahem Michnesei Vad" (28:42), what is meant by the prohibiton of "Lo Sigaleh Ervasecha Alav"?
Mechilta: To teach us that the Kohanim should ascend the Mizbe'ach in small steps (heel-to-toe and toe-to-heel) - and not in large steps. 1
Yerushalmi Berachos, 1:1: And that is why we Daven the Amidah with our legs close to one another - to be like the Kohanim. See Torah Temimah, note 134, who cites others who learn it from the Mal'achim, about whom the Navi writes ,"v'Ragleihem Regel Yesharah" (Yechezkel 1:6).
What are the ramifications of the prohibition against ascending the Mizbe'ach with steps?
Rashi: It teaches us that rather than steps to ascend the Mizbe'ach, they should manufacture a ramp. 1
What is the reason for the prohibition?
Rashi: Because when climbing up steps, one inevitably opens one's legs wide - and this is akin to revealing one's Ervah (even though the Kohanim wore pants which covered it), which is considered degrading in view of the Mizbe'ach's 1 Kedushah. 2
Ramban: It is out of respect for the Mizbe'ach, and in order to honor it, in honor of Hashem (in whose service it is being used).
Moshav Zekenim: Because the Mizbe'ach makes Shalom between Yisrael and Hashem, and (interpreting "v'Lo Sa'aleh b'Ma'alos" to incorporate a prohibition against haughtiness) 3 haughtines creates friction.
Moshav Zekenim: Why was the Torah concerned about the Mizbe'ach more than for other Keilim of the Mikdash? (What is his question? The only other Kli that needed ascent was the Menorah, and there his Ervah did not face the Menorah! Perhaps he asks why the Torah incorporates haughtiness on the Mizbe'ach. See answer #3 and note (PF).
Rashi: And if the Torah is particular about degrading stones, which feel no resentment, how much more so one's fellow-Jew, who is created in the image of Hashem and who is particular about his Kavod! Nazir 45a - And if the Torah is particular about an act that is not intrinsically degrading, how much more should a Nazir not shave off his hair at the entrance of the Ohel Mo'ed - See Torah Temimah, note 133.
However, the simple meaning refers to steps, since the Pasuk is discussing Giluy Ervah (PF)
What are the implications of the word "Asher Lo Sigaleh Ervasecha Alav"?
Mechilta: It implies that a Kohen may not take large steps when ascending the Mizbe'ach, but that he may do so when walking in the Heichal or (the Kohen Gadol) in the Kodesh Kodashim.
QUESTIONS ON RASHI
Rashi writes that if the Torah is particular about degrading stones, how much more so one's fellow-Jew. How can we learn from Hekdesh to a commoner?
Lev Eliyahu (p. 150): Because a Yisrael, who is created in the image of Hashem, is Kodesh Kodoshim.
