Commentary for Exodus 15:22

ויסע משה AND MOSES CAUSED [ISRAEL] TO JOURNEY — He made them journey against their own will, because the Egyptians had adorned their horses with ornaments of gold and silver and with precious stones, and the Israelites were finding these in the sea. Greater, indeed, was the booty they obtained at the Red Sea then the booty they had brought out of Egypt — as it is said (Song 1:11) “Circlets of gold (the booty of the Sea) will we make thee together with the studs of silver” (which we brought forth from Egypt) (Mekhilta d'Rabbi Yishmael 12:36). On this account he was compelled to make them journey on against their will.

ויסע משה את ישראל, Moses made Israel move on, etc. This was the only march which was initiated by Moses. Every subsequent move occurred at G'd's initiative.

ויסע, a causative construction, hiphil. When the Torah writes, as it does most of the time, vayisa, this is in the intransitive active mode, meaning “he journeyed,” instead of “he made (someone) journey,” as is the case here. Similar constructions involving both the kal mode and the hiphil mode of the verse are: vayagesh את פר החטאת, “he presented, brought near, the bull of the sin offering,” (Leviticus 8.14) as distinct from vayigash, “he approached (himself).” Similarly, a construction such as vayipol is in the intransitive active mode, meaning: “he fell, or he prostrated himself deliberately,” whereas the transitive mode of the same word (root) would be “vayapel,” “he threw down.”