והנה סלם. סלם בגימטריא סיני שראה דוגמא שעתיד הקב"ה לתת תורה לישראל על הר סיני: והנה סלם, “and here there was a ladder;” the numerical value of the letters in the word סלם=130, the same numerical value as the letters in the word סיני, “Sinai;” This was a hint that the Jewish people would receive the Torah at Mount Sinai. (B’reshit Rabbah, 68,12)
מוצב ארצה וגו'. וכנגד בסיני בוער באש עד לב השמים. והנה סולם מוצב ארצה , “and (in his dream) he saw a ladder planted on the earth;” at the burning bush, where Moses had his first communication from G–d, the fire from that bush rose to the heart of the heavens. At that time Moses was told specifically that the Israelites, Yaakov’s descendants shall worship G–d there.
והנה מלאכי אלהים. זה משה ואהרן. והנה מלאכי אלוקים, “and lo, prophets of G–d,” i.e. Moses and Aaron, would climb up and down there.
והנה ה' נצב עליו. זהו שנאמר וירד ה' על הר סיני. והנה ה' נצב עליו, and lo, the Lord was standing on top of it. This is what is meant when in Exodus 19,20, the Torah writes that the Lord descended to Mount Sinai.
ויאמר אני ה'. זהו שנאמר אנכי ה' אלהיך. ד"א סולם ממש והנה מלאכי אלהים הראה הקב"ה ליעקב שר של מצרים עולה (כדכתיב בפי' הרמב"ן ז"ל). ד"א והנה מלאכי אלהים עולים היינו המלאכים שהלכו להפוך את סדום שתלו הכבוד לעצמן שאמרו כי משחיתים אנחנו וגם גלו מסתורין של הקב"ה ולכך נדחו ממחיצתו של הקב"ה קל"ה שנים ועכשיו עלו: 'ויאמר אני ה, “He said: I am the Lord, etc.;” this parallels what Hashem said at the beginning of the Decalogue in Exodus, 20,2. An alternate interpretation; the word סולם is to be understood literally, as “ladder;” the words: והנה מלאכי אלוקים, describe G–d as showing Yaakov the spiritual representative of Egypt in the celestial spheres, (as also stated in the commentary by Nachmanides) and how that empire after first rising to great heights was brought down completely. A third interpretation: these angels were the angels that had come to Sodom to rescue Lot, and had been demoted by G–d after describing themselves to Lot as initiating the destruction of Sodom, by telling Lot that they had come to destroy Sodom, as if they had the power to do this instead of simply carrying out G–d’s command. (Genesis 19,14,) They had also revealed some of G–d’s secrets without having permission to do so. According to tradition, their punishment had been to be banned from the celestial regions. Now, 138 years later, they had been allowed to return to their places in the celestial regions.