"These are the journeys of the children of Israel..." (Num. 33:1)
Our verse may be understood when we consider what the Zohar (II:157) has to say about the purpose of the Israelites' trek through the desert: It was meant to enable the Israelites to seek out isolated sparks of sanctity and to release them from captivity. These "sparks" had been taken captive by the spiritually negative forces that have their home in the desert. G‑d made the Israelites travel through such places in order that their sanctity would act as a magnet and attract such "lost" sparks of sanctity.
The only way this could be accomplished was by means of total sanctity, [i.e.] a combination of the sanctity of Israel, the Shechinah and the holy Torah. It required the presence of 600,000 souls which originated in holy domains. Moses matched these 600,000 individually holy souls, as he is perceived of as the tree from which all these are branches (compare Isaiah 63:11). In a combined effort, these forces of sanctity were able to overcome the forces of impurity which kept many of these lost sparks of sanctity captive.
The Patriarchs…lacked this "completeness" which is predicated on the presence of 600,000 souls….
According to the Zohar, then these "sparks" could be captured while the Israelites were actively journeying and not while they were passively encamped; it is this the Torah had in mind when writing "these are the journeys". The word "these" [in Hebrew, "eleh"] is indeed in sharp contrast to any other journeys ever described anywhere, as never before had there been a journey which was accompanied by so many elements of sanctity.
While it is true that the Patriarchs have also been described as journeying, and they too rescued lost sparks of sanctity during their journeys, there is no comparison between what these individuals accomplished and what the Jewish nation as a whole accomplished in this regard. The Torah itself describes the superior nature of these journeys by stressing that they occurred as an aftermath of the Exodus from Egypt, i.e. after the Israelites had been refined in the Exodus from Egypt - after the Israelites had been refined in the iron crucible called Egypt. This enabled them to isolate sparks of sanctity wherever they would encounter them.
Not only that, but the Torah describes these journeys as haven taken place "letzivotam" (when they were a complete unit, the Shechinah resting on these 600,000 holy souls). We have described repeatedly that the definition of wholeness, completeness, is not applicable to fewer than 600,000 such souls.
You find that the reason G‑d did not give the Torah to the Patriarchs was due to their being too few in number. They lacked this "completeness" which is predicated on the presence of 600,000 souls which originated in a holy domain (compare Mechilta Yitro) so that they could be described as "tzevaot", "G‑d's armies". Only once the Israelites were in the desert did they comprise all the necessary pre-conditions for fulfilling the task set for them by their journeys. The Torah also added the phrase "under the guidance of Moses and Aaron", who were the "go-betweens" between the Shechinah and all the other elements of sanctity needed to fuse the nation into a single whole of sanctity.
[Selected with permission from the five-volume English edition of "Ohr HaChaim: the Torah Commentary of Rabbi Chaim Ben Attar" by Eliyahu Munk.]