What is the proof that Hashem is amidst them?
Rashi: You see that you all fit in this small place (between the staves). 1
Radak: It is what follows
Malbim: There are two ways that the Shechinah rests in Yisrael. (a) Like the heart, surrounded by the other limbs. (b) Like the brain, at the head of the body, and encompasses it intellectually. Moreh ha'Nevuchim (1:73) compares the big world with the microcosm (man). In the big world, more important things encompass less important things. The land, which is lowest of all, is encompassed by all. In man, it is opposite. What more important is internal and encompassed by all [the other limbs]. When Hashem (His Shechinah) is like the heart, He conducts [them] in a hidden way via natural means. When He is like the brain, He conducts [them] in a miraculous way. Here Hashem went in front of and encompassed them between the staves. Place, which is physical, did not obstruct. This shows that Hashem will dispossess the Kena'anim miraculously.