כִּ֣י אִם־שָׁמֹ֤עַ תִּשְׁמַע֙ בְּקֹל֔וֹ וְעָשִׂ֕יתָ כֹּ֖ל אֲשֶׁ֣ר אֲדַבֵּ֑ר וְאָֽיַבְתִּי֙ אֶת־אֹ֣יְבֶ֔יךָ וְצַרְתִּ֖י אֶת־צֹרְרֶֽיךָ׃
네가 그 목소리를 잘 청종하고 나의 모든 말대로 행하면 내가 네 원수에게 원수가 되고 네 대적에게 대적이 될지라
Sforno on Exodus
כי אם שמוע תשמע בקולו...ואיבתי את אויביך, My relationship to you then will not be protective, defensive, i.e. that I need to protect you, but aggressive, by treating your enemies as My enemies. This is the reverse of G’d’s attitude to Nineveh in Jonah 4,11 where G’d asked Jonah: “how can I not relate protectively to a city of over 120.000 people?”
Or HaChaim on Exodus
ואיבתי את אויביך, "For I will be an enemy unto your enemies, etc." Perhaps the Torah hints here that by means of busying oneself with Torah and the performance of its commandments G'd will uproot the source of the קליפה, i.e. Satan, as well as the various branches which are constantly active trying to seduce people and thereby to degrade and dishonour the banner of Torah. You are advised to read what I have written in connection with the confrontation between Cain and G'd in Genesis 4,9-15.