Rashi on Deuteronomy 33:27/רש"י על דברים ל״ג:כ״ז

1מענה אלהי קדם A DWELLING PLACE FOR THE ANCIENT GOD (This must be connected with the preceding): — The skies serve as a dwelling place for the ancient God, i.e. the God Who pre-existed (קדם) all gods, for He selected the skies as His residence and dwelling place, ומתחת AND BENEATH His dwelling place, all the mighty men (men of strong arm, זרוע) dwell.

2זרעת עולם THE ARMS OF THE WORLD are men such as Sihon and Og and the kings of Canaan who were the strength and might of the world. Therefore, since they are beneath God’s dwelling place, in spite of themselves they must tremble and quake, and their power prove frail in His presence, for always the fear of the one above falls upon him below, so that He, being above, to Whom therefore belong strength and power, is thy help.

3ויגרש מפניך אויב AND HE DROVE OUT THE ENEMY FROM BEFORE YOU, ויאמר AND HE SAID to you השמד DESTROY them!

4מענה — Every word that requires ל at its beginning, [Scripture] places (may place) a ה at its end instead (Yevamot 13b).