Deuteronomy 33:27

The habitation of Eloha is from eternity; by the arm of His power beneath the world is upborne. He will scatter your adversaries before you, and will say by His Word, Destroy them.

the ancient God is a shelter The word shelter means “booth” (as evidenced by “in Shalem is His booth, and His shelter in Zion” [Psalms 76: 3], and many similar passages). In other words: Your shelter is the ancient God. Compare, “you have made the Most High your shelter” [Psalms 91: 9] and “You have been a shelter for us” [Psalms 90: 1]. A shelter is always above that which is sheltered by it; the sheltered area is always beneath.

with His arms beneath to support you.

The sense of eternal is: Since they are forever, they will not weary. Similarly, your shelter will never pass away. because it is the ancient God (meaning, “primal”, with absolutely nothing antecedent to Him, nor anything that will succeed Him — for the concepts of “predecessor” and “successor” apply only to material things). Sa‘adya Gaon understood beneath to mean “below God ”, but this explanation is vacuous.

אלוקי קדם, the true G’d ever since the beginning of all existence. Anything that is of more recent origin has been called into existence by this G’d.

ומתחת זרועות עולם; beneath the heavens this G’d manifests Himself as the G’d of everlasting arms, (in the sense of extensions of His essence) mortal rulers whose power is of short duration, even the supposed basic elements, as well as what we call nature, the phenomena supplying nourishment for all he mortal forms of life on earth, including the ability to procreate.

ויגרש מפניך אויב, He, this eternal G’d, expelled on your account the inhabitants that inhabited the land promised to your forefathers by Him. He had said to you: השמד!, “destroy!” For you certainly did not conquer this land by force of arms with your sword, so that you would be afraid of losing it after a time, when your strength would ebb, as does the strength of every conquering nation after a while. Seeing that it had not been you who had driven them out, you have no reason to fear a natural erosion of your power to hold on to this land. [Only the One Who has expelled them is in a position to expel you if you give Him reason to do so. Ed.]

מעונה אלוקי קדם, “the ancient G–d is a source of refuge;” the heavens are G–d’s residence, He Who preceded everything and everyone else.

ומתחת זרועות עולם, “and underneath (as support) are the ever-lasting arms;” The G–d in heaven also supports the universe below that He has created. He is the ruler of both the “upper” regions and the “lower” regions in the universe.

ויגרש מפניך אויב, “He will expel every enemy from before you,”

ויאמר: השמד, “by simply ordering (His agent), in this case the Jewish people, by saying to them “destroy Amalek utterly,” as in Deuteronomy 25,19. The era when this order will be given a second time, [it had been given a first time to the first Jewish King Sha-ul, who had not completely carried it out, Ed.] will be only after the Jewish people are no longer under attack or even afraid of attack from the gentiles. One of the conditions for that time having arrived is spelled out by the prophet Bileam in Numbers 23,9 when he described the Jewish people as not feeling part of the “United Nations,” but as residing in solitary splendour, perfectly content in their role.