What is "Anochi Omeid bein Hashem u'Veineichem" referring to?
Ramban #1: It refers to the number of times Moshe ascended and descended Har Sinai prior to the Aseres ha'Dibros. 1
Ramban #2 (citing Ibn Ezra): It refers to after Ma'amad Har Sinai, when Moshe began to act as the intermediary between Hashem and the people. 2
Ramban #3: It refers to the last eight of the Aseres ha'Dibros, which Yisrael were unable to understand when they emerged from the Mouth of Hashem. 3
How does the word "Leimor" fit in?
Rashi, Ramban #1 (citing Ibn Ezra #1), Rashbam and Seforno: It refers to "Panim be'Fanim Diber Hashem imachem .... Leimor" in Pasuk 4. 1
Ramban #2 (citing Ibn Ezra #2): It refers to the phrase (in the same Pasuk 2 ) "Lehagid lachem es D'var Hashem ... Leimor".
Targum Yonasan: It follows "ve'Lo Alisem ba'Haf" and translates as 'and you did ascend the mountain when He said "Anochi ... " '.