יִתֵּ֨ן יְהוָ֤ה אֶת־אֹיְבֶ֙יךָ֙ הַקָּמִ֣ים עָלֶ֔יךָ נִגָּפִ֖ים לְפָנֶ֑יךָ בְּדֶ֤רֶךְ אֶחָד֙ יֵצְא֣וּ אֵלֶ֔יךָ וּבְשִׁבְעָ֥ה דְרָכִ֖ים יָנ֥וּסוּ לְפָנֶֽיךָ׃
The LORD will cause thine enemies that rise up against thee to be smitten before thee; they shall come out against thee one way, and shall flee before thee seven ways.
Rashi on Deuteronomy
ובשבעה דרכים ינוסו לפניך AND THEY SHALL RUN AWAY BEFORE THEE SEVEN WAYS — Such is the manner of all who flee out of fear: they scatter in every direction.
Tur HaArokh
הקמים עליך, “the ones that rise up against you.” Seeing that Moses had already blessed them by describing them as supreme among the nations, he now has to assure them that even if other nations should rear their heads trying to attack them, G’d will see to it that they are defeated in short order.
Siftei Chakhamim
By scattering in every direction. Why then it is written “seven”? Re”m explains that it is customary for “seven” to represent an expression of multiplicity, as in (Shmuel I 2:5), “Until the barren gives birth to seven, etc.”