John Calvin Commentary Numbers 10:35

"And it came to pass, when the ark set forward, that Moses said, Rise up, O Jehovah, and let thine enemies be scattered; and let them that hate thee flee before thee." — Numbers 10:35 (ASV)

And it came to pass, when the ark set forward. Since their journey was by no means a peaceful one, and the attack of enemies was constantly to be feared, it was necessary to implore God that He would go forth as if prepared for battle. In this way, Moses also supported their courage, lest any more immediate cause for terror should render them sluggish and inactive.

It is, then, as if he had prayed in this way: "O Lord, not only show us the way, but open it to us also by the power of your hand in the destruction of the enemies." He calls them not the enemies of the people but of God, so that the Israelites might be assured that they fought under His auspices. For in this way a more certain victory might also be expected, since the righteous God, who avenges iniquity, was defending His own cause.

And it was also no small matter of comfort and rejoicing when the people heard that whoever arose to harass them unjustly were also the enemies of God, since He will protect his people as the apple of His eye.

Therefore, the Prophet has borrowed this passage to arm the Church with confidence and to maintain it in cheerfulness under the violent assaults of its enemies (Psalms 68:1).

Furthermore, the analogy and similarity between the visible sign and the thing signified must be observed, for Moses was not so foolish as to address the Ark in these words; he only asked God to prove effectively that the Ark was a living image of His power and glory.