מאסף כל המחנות, “as the rearguard of all the camps;” the word מאסף, which literally means “ingathering,” was chosen here as this tribe was responsible to see to it that any stragglers who for one reason or another had not been able to keep up with the pace of the rest of the people, would not be left behind.

כי על כן ידעת חנותנו במדבר, “for you know how we can best make camp in the desert.” [Moses tries to make Yitro feel that his presence has become indispensable for the Jewish people. Ed.] He also implied that seeing that his father-in-law had become a witness to the miracle G–d performed daily for His people, how could he leave them at this juncture?

וארון ברית ה' נוסע לפניהם, “and the Holy Ark of the Covenant with Hashem traveled in front of them. During each night the Divine cloud was resting above the Holy Ark. Clearly the Israelites had not been able to travel without resting for three days and three nights. Jewish law rules that if someone swears an oath that he would not three for three consecutive days, i.e. for 72 hours, he will be subjected to the penalty of 39 lashes, as he undertook something he knew he would not be able to fulfill. (Talmud, tractate Shavuot, folio 25.) The cloud would resume its position above the camp of the Israelites in the morning, and the Levites would make the necessary preparations before the main body of the people resumed travelling. This is the plain meaning of the words: נוסע לפניהם, “was travelling ahead of them.” The Holy Ark was a distance of three days’ walking on foot in front of the main body until the people came to Kadesh in the desert of Paran. (Numbers 13,3) From then on they travelled without the Holy Ark, as we know from Numbers 14,44, when Moses did not allow the ones who were then willing to try and conquer the land of Canaan to take the Holy Ark with them. The meaning of the words: דרך שלשת ימים , is “a distance of three days’ march. This construction is also found when the Torah describes G–d as having created the universe in six days, i.e. ששת ימים. (Exodus 20,11)

'קומה ה' וגו, “rise up O Lord, etc.” this is a prayer that if enemies will gather to attack the Israelites they should be dispersed by G–d before carrying out their plans. If, for some reason they had already succeeded in massing, G–d should put them to flight. [In both instances Israel’s enemies are described as G–d’s enemies by definition. Ed.]

'ובנחה יאמר וגו, “and when it rested he would say, etc;” Moses would say when the cloud came to rest above the Tabernacle: ‘may the hundreds of thousands of Israelites rest in this place without diminishing in numbers. May their next departure find them without any of them being absent or missing.’ Compare (Deuteronomy 30,3)