Reference for Deuteronomy 31:4

וְעָשָׂ֤ה יְהוָה֙ לָהֶ֔ם כַּאֲשֶׁ֣ר עָשָׂ֗ה לְסִיח֥וֹן וּלְע֛וֹג מַלְכֵ֥י הָאֱמֹרִ֖י וּלְאַרְצָ֑ם אֲשֶׁ֥ר הִשְׁמִ֖יד אֹתָֽם׃

And the LORD will do unto them as He did to Sihon and to Og, the kings of the Amorites, and unto their land; whom He destroyed.

BDB