Sforno on Deuteronomy 33:27/ספורנו על דברים ל״ג:כ״ז

1אלוקי 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.

2ומתחת 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.

3ויגרש 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.]