וְאַתֶּ֣ם רְאִיתֶ֗ם אֵת֩ כָּל־אֲשֶׁ֨ר עָשָׂ֜ה יְהוָ֧ה אֱלֹהֵיכֶ֛ם לְכָל־הַגּוֹיִ֥ם הָאֵ֖לֶּה מִפְּנֵיכֶ֑ם כִּ֚י יְהוָ֣ה אֱלֹהֵיכֶ֔ם ה֖וּא הַנִּלְחָ֥ם לָכֶֽם׃
And ye have seen all that the LORD your God hath done unto all these nations because of you; for the LORD your God, He it is that hath fought for you.
Read midrashic interpretation of Joshua 23:3: and classical rabbinic exegesis.